iOS Issue Categories - harishkumar12k/Swift GitHub Wiki

🔧 1. Performance Issues

Slow app performance
UI lag or stutter
High CPU or memory usage
Battery drain caused by apps
Background task ineﬃciency

🧱 2. UI/UX Bugs

Layout issues on diﬀerent screen sizes
Unresponsive UI elements
Misaligned or missing components
Dark mode incompatibility
VoiceOver/accessibility bugs

📱 3. App Crashes

Crash on launch
Crash due to unhandled exceptions
Memory-related crashes (e.g. out-of-memory errors)
Threading/concurrency issues

🌐 4. Networking Issues

Connectivity errors
Slow or failed API requests
Background fetch failures
Improper error handling for oﬄine scenarios

🔒 5. Security & Privacy

Data leaks (e.g. logging sensitive info)
Improper data storage (not using Keychain, etc.)
Privacy permission mismanagement
Insecure networking (HTTP instead of HTTPS)

🧩 6. Compatibility Issues

Incompatibility with newer iOS versions
Deprecated API usage
Issues on specific device models
Framework or third-party SDK issues

📤 7. App Store Deployment Issues

Code signing problems
Provisioning profile errors
App Store review rejections
Build/archive problems in Xcode

🔁 8. Update/Migration Issues

Data migration bugs
Problems after iOS version updates
Database schema mismatch
iCloud sync issues

🔔 9. Notifications Issues

Push notifications not arriving
Notification permissions not handled
Improper deep linking from notifications
Badge count not updating

⌚ 10. Device-Specific Features

Camera/Photos access issues
Bluetooth, GPS, or NFC not working
Face ID/Touch ID bugs
Widgets, App Clips, or Shortcuts misbehaving

🧪 11. Testing & Debugging Issues

Inconsistent behavior in simulator vs. real device
Unit/UI tests failing without clear reason
TestFlight distribution problems
Debug symbols missing (e.g. for crash logs)

📍 12. Location Services Issues

Inaccurate location tracking
Failure to request/update location permissions
App not updating location in background
Geofencing not triggering properly

🧠 13. Core ML / AI Integration Issues

Model loading failures
On-device inference performance issues
Incorrect outputs from models
Incompatibility with iOS version or hardware

🎮 14. Media & Graphics Issues

Audio playback glitches
Video rendering problems
Metal/OpenGL bugs
Camera feed not displaying correctly
Image asset scaling or format issues

🧩 15. Framework-Specific Bugs

Core Data migration failures
SwiftUI state/rendering issues
Combine or async/await logic bugs
ARKit/SceneKit glitches
HealthKit/HomeKit/WatchKit issues

🌍 16. Localization & Internationalization Issues

Text not translating correctly
Layout breakage in RTL (right-to-left) languages
Date/time/currency formatting errors
Region-specific behavior not working

🔃 17. Syncing & State Management Problems

iCloud Drive sync issues
Core Data iCloud conflicts
State restoration not working
UserDefaults or app storage inconsistencies

🎯 18. Haptics & Sensor Feedback

Taptic engine not triggering as expected
Accelerometer/gyroscope not responding
Incorrect motion or sensor data

💬 19. App Communication Issues

Deep linking failures
Universal Links not opening properly
Inter-app communication (e.g., via URL schemes) issues
Handoﬀ/Continuity bugs between Apple devices

📦 20. Third-Party SDK & Dependency Problems

CocoaPods/Carthage/SPM version conflicts
SDKs breaking after iOS update
Analytics/tracking SDK issues
In-app purchase frameworks not working

🧬 21. Memory Management & Retain Cycle Issues

Retain cycles causing memory leaks
Over-retaining views/controllers
Deallocation not happening as expected
Improper ARC usage (rare but possible in mixed Obj-C/Swift)

⏱ 22. Timing & Race Conditions

Async code executing out of order
Race conditions in shared resources
Delays in UI updates
Issues with DispatchQueue or NSOperationQueue

📱 23. Multi-Window / Scene Delegate Issues

State not syncing between multiple windows
SceneDelegate lifecycle bugs
Split-view/multi-tasking misbehavior on iPad

🧾 24. App Entitlement & Capability Issues

Missing or misconfigured entitlements
Capabilities not enabled in provisioning
iCloud/Push/HealthKit entitlements failing silently

🧩 25. Cross-Version or Legacy Support Bugs

APIs behaving diﬀerently across iOS versions
Unsupported features causing silent failures on old devices
Swift/Obj-C bridging issues in legacy codebases

🧿 26. Gesture Recognition Issues

Conflicts between gesture recognizers
Gestures not firing inside scroll views
Custom gestures breaking native behavior

🛸 27. Background Task Issues

App being killed unexpectedly in background
Background fetch not running reliably
Background processing limits not respected
Audio or navigation apps not maintaining background mode

🕵 28. Privacy Labels & App Transparency Issues

Incorrect App Store privacy declarations
App Tracking Transparency (ATT) dialog not appearing
Tracking permission logic not working correctly

🪝 29. Notification Extension or Widget Problems

Notification content extensions crashing
WidgetKit bugs (e.g., timeline not updating)
Widgets not appearing or launching app properly

🌊 30. File & Data Handling Issues

Sandbox violations
Failure to access documents directory properly
Corrupted file reads/writes
Poor error handling for file system permissions

🧼 31. Clean Architecture & Modularization Issues

Improper separation of concerns (e.g., bloated ViewControllers)
Hardcoded dependencies (no DI)
Tightly coupled modules making testing & maintenance hard
Reusability problems due to poor module design

🧮 32. Precision & Numeric Bugs

Rounding or precision errors (especially in finance or measurement apps)
Locale-sensitive number formatting
Incorrect floating-point comparisons
Unexpected overflow/underflow in calculations

🧰 33. Build System / CI/CD Problems

Xcode build configuration conflicts
Script phase failures
Broken CI pipelines (Bitrise, GitHub Actions, Jenkins, etc.)
Dependency resolution failures in automated builds

🧬 34. Swift Compiler or Language Quirks

Type inference confusion
Associated type constraints failing mysteriously
Silent bugs due to optionals or forced unwraps
Generics causing compile-time headaches

🕳 35. Edge-Case Lifecycle Bugs

Unusual AppDelegate/SceneDelegate call orders
Lifecycle confusion during fast app switching
App state inconsistencies after low-memory kill & restore
Incorrect state restoration behavior

🗂 36. Accessibility & Compliance Edge Cases

VoiceOver reading out dynamic content improperly
Dynamic type support breaking UI
Missing accessibility labels in custom views
Color contrast not meeting WCAG standards

⚡ 37. Energy & Thermal Issues

High background activity leading to device heating
App being throttled by iOS due to thermal pressure
Animations draining GPU cycles unnecessarily
Unoptimized timers waking CPU frequently

🕹 38. Input & Keyboard Issues

Keyboard covering input fields
Custom keyboard extensions breaking
Text input bugs on external keyboards
Keyboard dismissal not behaving correctly

🛰 39. App Transport Security (ATS) Problems

Blocked HTTP requests due to missing ATS exceptions
Misconfigured Info.plist for secure connections
Rejected connections due to TLS version restrictions

🔗 40. App Extension & Shared Container Issues

Shared data between main app and extensions not syncing
Extension crashing due to size/memory constraints
App Groups not properly configured
Security concerns with shared containers

🧭 41. Navigation & Routing Issues

Improper back stack behavior in UINavigationController
Memory leaks from pushed/presented view controllers
Deep links bypassing auth or validation logic
State inconsistency from restoring saved routes

Obfuscation & Reverse Engineering Vulnerabilities

Lack of code obfuscation in release builds
Jailbreak detection easily bypassed
App logic exposed via disassembly
Insecure handling of API keys or secrets

🧨 43. Swift Concurrency & Actors Issues

Improper use of @MainActor leading to UI glitches
Data races due to missing isolation
Deadlocks in async/await patterns
Tasks being cancelled unexpectedly

🧫 44. Simulator-Only vs Real Device Bugs

Features working fine on simulator but breaking on real devices (camera, Bluetooth, etc.)
Performance wildly diﬀerent in production hardware
Push notifications or background modes faking success in simulator

🧊 45. Frozen UI & Deadlock Scenarios

Main thread blocking due to heavy sync tasks
Recursive dispatch queues causing app freeze
Deadlocks with semaphores or GCD barriers
UI hung from modal presentation deadlocks

🕳 46. iOS System Quirks & Undocumented Behavior

Silent permission resets after updates
Weird behavior from low battery/power-saving modes
iOS bug in specific minor versions causing layout or crash issues
Background modes silently disabled by iOS due to misuse

🧩 47. App Group / Shared Data Corruption

Data collisions between app & widget
Shared UserDefaults behaving inconsistently
Race conditions in shared containers
Corrupted files due to simultaneous writes from multiple targets

💸 48. In-App Purchase (IAP) & StoreKit Bugs

Transactions stuck in pending or failed state
Receipt validation issues (especially on server)
Sandbox vs. production environment confusion
Subscription renewals not handled gracefully

🔃 49. Migration & Versioning Problems

App updates breaking older cached data
Core Data schema changes not properly migrated
Version checking logic failing on edge versions
Backward compatibility testing skipped (and it shows)

🧪 50. Test Environment & Mocking Bugs

Mocks/stubs behaving diﬀerently from real APIs
Snapshot tests failing due to minor UI shifts
Test data leaking into production builds
Integration tests passing locally, failing in CI (or vice versa)

📦 51. App Extension Conflicts

App extensions trying to access resources incorrectly
Extension UI not appearing correctly on certain iOS versions
Data synchronization issues between the main app and extensions
Extension crashing due to low memory or limited CPU on background tasks

🧪 52. Test Automation Failures

UI automation tests flaking due to timing issues
Misconfigured simulators causing false positives/negatives
UI tests not accounting for screen size or resolution variations
Test failures due to iOS background app refresh interfering with tests

⚠ 53. App Lifecycle Edge Cases

App crashing when moving from background to foreground after a long time
Notifications not appearing after app suspension
App not restoring state after a force quit
Issues with app lifecycle methods on multi-screen devices (like iPads)

🔒 54. Data Privacy & Encryption Issues

Sensitive data stored insecurely in user defaults or local files
App not respecting user data encryption settings
Flaws in data encryption at rest (CoreData, files)
Exposing sensitive data in error logs or stack traces

🪞 55. Interface Builder (IB) & Storyboard Bugs

IB bugs causing view hierarchy to become corrupted
AutoLayout constraints causing views to be misplaced in IB but working fine at
runtime
Storyboard merge conflicts during version control integration
Unintended behavior when transitioning between devices with diﬀerent screen sizes

📞 56. CallKit & VoIP Issues

VoIP app not receiving push notifications reliably
CallKit UI misbehaving when backgrounding or foregrounding the app
Incoming call notification delays due to network issues
CallKit audio routing failing to respect user settings (e.g., switching to speaker automatically)

🌐 57. WebView & WKWebView Bugs

JavaScript injection failing due to Content Security Policy (CSP) restrictions
WebView not loading content correctly in low bandwidth
JavaScript errors crashing WebView in certain conditions
WebView not rendering custom fonts or CSS as expected

📶 58. Network Connectivity Fluctuations

App inconsistencies when switching between WiFi and cellular data
Oﬄine-first apps failing to sync data when back online
Handling network timeouts gracefully in real-time apps
WiFi/Cellular transition issues when apps are running in the background

🖼 59. Image & Asset Handling

Image not rendering at diﬀerent device resolutions (1x, 2x, 3x)
Memory leaks or crashes when loading large images
UIImageView not respecting image aspect ratio in certain layouts
Issues with animated images (GIF, APNG) rendering inconsistently

🔀 60. Core Animation & Rendering Issues

Animations stuttering due to high CPU/GPU usage
Layer-based animation glitches when running on low-performance devices
Unresponsive animations after navigating between view controllers
Z-index issues or layering problems with subviews in animation stacks

📍 61. GPS/Location Accuracy Bugs

Inaccurate GPS coordinates under certain conditions (high-rise buildings, tunnels, etc.)
Location updates freezing or lagging in background
Issues with geofencing not firing when app is in background or terminated
App failing to request or handle location permissions properly

📡 62. Bluetooth Connectivity Issues

Bluetooth peripherals not reconnecting after app is closed
Low-energy Bluetooth (BLE) connections failing intermittently
Background Bluetooth scanning issues
Inconsistent behavior when switching between paired devices

� 63. App Delegate & Scene Delegate Conflicts

SceneDelegate causing unexpected UI behavior when interacting with AppDelegate
State restoration issues when switching between diﬀerent scene configurations
AppDelegate lifecycle methods not firing correctly on iPhone vs. iPad
Multi-window apps breaking when AppDelegate and SceneDelegate conflict

🧳 64. Multithreading & Background Task Bugs

Main thread blocking from background tasks leading to UI freezes
Background fetch tasks not resuming after app goes into the background
Concurrency issues when sharing data across multiple threads
Race conditions when accessing shared resources in multi-threaded environments

📲 65. App Icon & Launch Screen Bugs

App icon not updating in some cases after an app update
Launch screen flicker on app startup due to improper image sizes
App icon not showing correctly in diﬀerent device modes (dark mode, low-power mode)
Launch screen not loading at the correct resolution on certain devices

🪄 66. Custom Transitions & Navigation Issues

Custom transition animations failing when transitioning between view controllers
Unexpected behavior when using custom navigation controllers or tab bar controllers
Navigation bar issues when pushing or popping views with custom transitions
Custom modal transitions not aligning with system expectations (i.e., iPhone SE vs. iPhone 12 Pro)

💬 67. Messaging & Real-Time Data Syncing Bugs

Push notifications arriving late or not at all in real-time messaging apps
Messages not syncing properly across devices (iMessage, Firebase, etc.)
Real-time updates failing when app is in background or suspended
Notifications not respecting user preferences for do-not-disturb settings

⏳ 68. Delayed App Launch or Initial Load

App taking too long to launch due to heavy background tasks
Initial data load or first-time setup taking excessive time
App launch being blocked by background processes or database syncing
User-facing delay due to large app package size or dependencies

🖥 69. Remote Configuration or Feature Flags Issues

Remote configuration failing to load correctly after an app update
Feature flags not being respected or causing crashes in production
App failing to handle missing or invalid remote config data
Inconsistent feature behavior across diﬀerent user groups or environments

🛠 70. Xcode & Build Issues

Xcode refusing to build due to provisioning profile issues (code signing conflicts)
Xcode running out of memory or freezing during large builds
Misleading error messages or undefined symbols during builds
Build time inconsistencies across diﬀerent macOS versions or Xcode setups

🧳 71. iCloud Syncing & CloudKit Issues

Syncing conflicts between local and cloud-stored data
Data not updating across devices due to iCloud syncing delays
CloudKit API limits causing unexpected failures in high-traﬃc apps
User permissions failing silently during iCloud setup

⚡ 72. Performance Bottlenecks (Advanced)

Heavy CPU or GPU usage from complex views or layouts
Unoptimized background threads leading to UI lag
Memory fragmentation issues in long-running apps
Cache invalidation or overuse of caching leading to slowdowns

🖥 73. WebKit & JavaScript Runtime Issues

JavaScript code execution failures within WKWebView
WebView not rendering custom JavaScript frameworks correctly
CORS (Cross-Origin Resource Sharing) issues in WebView
WebKit crashes when rendering heavy or complex HTML5 elements

⏰ 74. Timezone & Calendar Bugs

Incorrect timezone handling when displaying dates/times in international apps
Daylight saving time causing shifts in scheduling logic
Timezone-aware calendars not synchronizing properly across devices
Inaccurate recurring event calculations in calendar apps

🔒 75. App Sandboxing & Permissions Issues

Sandbox permissions causing app crashes or data loss
iOS security model conflicting with custom app behaviors
App not respecting restricted access to resources (camera, microphone, etc.)
App sandbox violations leading to app rejection by Apple

🌐 76. Internet of Things (IoT) Integration Bugs

Bluetooth communication inconsistencies with IoT devices
Sensor data failing to sync with central hub or cloud
Low-power modes aﬀecting IoT device behavior
Security issues with IoT integrations (e.g., unencrypted communication)

🌙 77. Dark Mode Compatibility

UI elements not switching correctly between light and dark modes
Third-party frameworks not supporting dynamic colors in dark mode
Images or assets not optimized for both light and dark themes
Inconsistent appearance of components in dark mode across iOS versions

💻 78. macOS Catalyst Issues

UI/UX diﬀerences when running iPad apps on macOS
App crashes or misbehavior when transitioning from iOS to macOS
Touch-based interactions not behaving as expected on macOS
App not respecting macOS-specific features (menu bar, keyboard shortcuts, etc.)

📶 79. Push Notification & APNs Issues

Push notifications not arriving immediately after app launch
Silent push notifications failing due to misconfigured payload
Push notification permission dialog not showing correctly in certain cases
Push notifications not showing badges or updating icon count

🌐 80. Networking & API Rate Limiting

Network retries causing excessive load on the backend
API rate limits being reached, causing unexpected app failures
Network latency causing timeout errors or app crashes
Background networking tasks failing due to system limitations or poor handling

🛠 81. Continuous Integration/Continuous Deployment (CI/CD) Challenges

Build artifacts not syncing properly with distribution channels (TestFlight, App Store)
Failing to update or invalidate cached dependencies (CocoaPods, SPM, Carthage)
Test environments inconsistent across diﬀerent CI servers
Artifacts from previous builds causing issues with the latest version

🔄 82. Data Synchronization Issues Across Multiple Devices

User data not syncing across devices after a change
Conflicting data from simultaneous edits (e.g., editing a document on multiple devices)
Local changes not propagated to the cloud (or vice versa)
Inconsistent synchronization during app state restoration

⚙ 83. Advanced AutoLayout & Constraints Problems

Constraint conflicts that only appear at runtime, not during layout
AutoLayout failure in multi-device environments (i.e., iPad vs. iPhone)
Stack views not resizing correctly with dynamic content
Constraint issues with dynamically-loaded content (e.g., web views, third-party components)

🎧 84. Audio & Video Streaming Bugs

Buﬀering issues with streaming audio or video content
Audio interruptions not handled gracefully (e.g., incoming call, background apps)
Audio playing in the wrong route (e.g., through speaker instead of headphones)
Video orientation issues during streaming (portrait vs. landscape)

🕹 85. Game-Specific Bugs (SpriteKit, SceneKit, Metal)

Performance drops in game engines due to excessive frame rendering
Physics engine conflicts leading to erratic object movements
Unresponsive or delayed touch input in high-performance games
Memory leak from improperly managed textures and assets

🧩 86. Complex Data Structures & Serialization Issues

Encoding/decoding failures with complex JSON or XML data
Corrupted data during JSON parsing due to unexpected formats
Issues with mapping complex objects (nested arrays, dictionaries) to models
Data inconsistency when serializing large amounts of data for storage or transfer

📦 87. App Store Rejection Issues

Rejection due to non-compliance with App Store guidelines (UI/UX, permissions)
Incorrect or missing privacy policy causing app rejection
Unclear app functionality leading to app rejection (e.g., apps not fully functioning)
In-app purchases not set up correctly causing rejection during review

🔐 88. Advanced Security & Authentication Bugs

Improper use of Keychain leading to data leakage
Silent failure of biometric authentication (Face ID, Touch ID)
Weak password policies not being enforced (leading to account compromise)
Session management errors causing users to stay logged in after session expiry

🧠 89. Core Data Performance and Faulting Issues

Fetch requests causing memory spikes (especially with large datasets)
Faulting and pre-fetching issues when accessing Core Data objects
Data persistence failures or corruption under heavy load
Inconsistent behavior when migrating Core Data schemas

🏃 90. UI Performance & Threading Issues

UI lag due to unnecessary background tasks running on the main thread
Animations not rendering smoothly on lower-end devices
UI flickering when transitioning between diﬀerent view controllers
Delayed UI updates after long-running network requests

🔄 91. Background Task Management

Background fetch not triggering on specific devices or conditions
Background audio or location tracking failing after app enters background
App terminating background tasks unexpectedly when switching between apps
Incorrect behavior when using background URLSession for long-running uploads/downloads

🧪 92. In-App Debugging & Logging Issues

Log output not showing up during testing in certain environments (e.g., release mode)
Debugging symbols stripped or missing in production builds, making stack traces unreadable
Verbose logging slowing down app performance
App crashes not providing enough information in logs to diagnose root causes

🌎 93. Localization & Internationalization Issues

UI elements getting cut oﬀ due to long translations in other languages
Localized date, time, and number formatting not working correctly
Right-to-left (RTL) languages causing layout breakages
Missing or incorrect translations in app strings, leading to poor user experience

🏗 94. Modularization & Code Split Problems

Code split issues causing incorrect or slow module loading at runtime
Unexpected app crashes due to missing module dependencies
Circular dependencies when attempting to modularize large apps
Performance hits from incorrectly implemented code splitting (e.g., slow app startup)

💡 95. Dynamic UI Elements & Rendering Bugs

Dynamic content (like text or images) causing layout shifts during animations
Dynamic UI elements causing intermittent clipping or visibility issues
Custom UI components not adapting well to diﬀerent screen sizes or orientations
Performance degradation when rendering highly dynamic views (e.g., large lists)

🧱 96. Complex Gesture Handling

Custom gesture recognizers interfering with native iOS gestures
Simultaneous gesture recognition issues (e.g., swipe and tap conflicts)
Incorrect gesture handling when the app is backgrounded or suspended
Gesture lag or missed input during complex view transitions

🔑 97. Keychain & Sensitive Data Management

Inconsistent access to data stored in the Keychain across app installs
Keychain data corruption during app upgrade or version migration
Lack of proper data encryption when using Keychain for sensitive information
App failing to store or retrieve credentials in specific iOS versions

� 98. Debugging Crash Reports in Production

Crash reports from third-party libraries being diﬃcult to decipher
No stack trace or missing information due to stripped debug symbols in production builds
App crashing only under specific, rare conditions that don’t appear during testing
Crashlytics or other crash reporting tools not capturing full crash details

🛠 99. Toolchain Compatibility & Version Issues

Xcode and macOS version incompatibility aﬀecting builds
Deprecation warnings leading to broken code on new Xcode or iOS versions
SDK versions mismatching with app’s current codebase (iOS 16 SDK vs. iOS 15 SDK)
CocoaPods, Carthage, and Swift Package Manager conflicts in dependency resolution

🧭 100. App Data Consistency Across Multiple Platforms

Syncing issues between iOS and watchOS/ tvOS apps
Data corruption when switching between devices using the same iCloud account
Inconsistent state between iOS app and companion apps (iPad app, macOS app)
App performance and state discrepancies when running across diﬀerent versions of iOS

🧿 101. Sensor & Motion API Issues

Inconsistent gyroscope or accelerometer data across devices
Motion updates stopping after backgrounding the app
Magnetometer readings fluctuating due to hardware or environmental interference
Battery drain from frequent sensor polling

🔁 102. App Update & Migration Edge Cases

Users skipping multiple versions causing migration logic to fail
App update corrupting local storage or user defaults
Inconsistent Core Data migration when old builds remain installed
Silent failures during schema or file format migrations

🎮 103. External Hardware Integration (MFi, USB, NFC)

MFi accessory connections dropping intermittently
NFC sessions failing or timing out unpredictably
USB communication behaving diﬀerently between devices
Issues with Lightning or USB-C accessories post-iOS update

🖥 104. Shared Codebase Bugs (Cross-Platform)

Bugs introduced by shared business logic (e.g., in multiplatform Swift code)
Platform-specific features not handled correctly in shared modules
Build configurations clashing between iOS, macOS, and watchOS
Runtime errors due to environment-specific conditionals not being enforced properly

🌌 105. Real-Time Communication Bugs (VoIP , Chat, Video)

Connection drops under poor network without proper reconnection logic
Media streams getting out of sync (video-audio desync)
Latency spikes in live chat or calls not being caught by monitoring tools
Inconsistent session states across users (e.g., one user sees “connected” while the other doesn’t)

🗺 106. App Distribution & Enterprise Deployment Issues

Problems distributing via MDM (Mobile Device Management) systems
Enterprise-signed builds not installing on managed devices
App installations failing due to certificate expiry or revoked profiles
Version conflicts when updating internally-distributed builds

🌡 107. Thermal Throttling & Hardware-Triggered Limitations

Performance suddenly dropping due to heat (esp. in games or heavy apps)
Animations jittering under thermal pressure
Camera access being denied due to device temperature
Unexpected suspension of background tasks when CPU overheats

🧾 108. App Review Metadata & Policy Issues

Metadata not matching app functionality (resulting in App Store rejection)
Screenshots or descriptions misleading or outdated
In-app purchases or services violating Apple’s guidelines
Hidden features being flagged by App Review tools or AI scanning

🧊 109. Low Storage or Memory Scenarios

App crashing when trying to write to disk under low-storage conditions
iOS purging cache or temp data unexpectedly
Memory warnings not being handled gracefully (leading to crashes or lost user data)
Core Data or file-based storage failing silently when disk is nearly full

🧠 110. Machine Learning / On-Device Model Bugs

ML model not compatible with certain iOS or hardware versions
Inconsistent predictions due to diﬀerences in model quantization
CoreML model file corrupted during OTA update
Slow inference or model loading under high memory pressure

🧠 111. On-Device AI & Personalization Bugs

ML model personalization failing due to insuﬃcient device permissions
Models learning incorrect behavior due to edge-case user data
Model corruption during real-time training updates
CoreML model not releasing memory properly, leading to crashes

🧳 112. Advanced Oﬄine Mode & Sync Conflicts

Oﬄine edits overwriting online data without proper resolution
Failed syncs silently ignored by the app (data appears lost)
Caching logic creating duplicate entries on reconnection
Sync retries never triggering due to background restrictions

🌩 113. Cloud Functions / Serverless Integration Bugs

Failure to handle timeouts and cold starts in serverless APIs
Uncaught exceptions in cloud functions crashing client-side logic
Incorrect region deployment causing unexpected latency spikes
Mismatch in auth/headers when calling serverless APIs from iOS

🔗 114. Deep Linking & Universal Link Edge Cases

Universal links not opening the app on older iOS versions
Multiple installed apps claiming the same link path
Link handling logic broken by SceneDelegate transitions
Broken fallback to web content when app isn’t installed

📱 115. App Clip-Specific Issues

App Clip not triggering when scanning QR/NFC
Unexpected permissions denials due to App Clip limits
State loss when transitioning from App Clip to full app
Performance bottlenecks from trying to load too much in the App Clip

🧬 116. HealthKit / ResearchKit Integration Problems

Data not syncing properly due to revoked permissions
Health data units mismatching expected formats (e.g., mg/dL vs mmol/L)
Missing entitlements causing silent failures in data access
User confusion from duplicate consent screens in onboarding

🧾 117. Subscription Management & Renewal Issues

App not handling interrupted purchases or billing errors
Inconsistent behavior across territories (sandbox vs production quirks)
App thinking subscription expired due to cache lag
Issues with restoring purchases across diﬀerent Apple IDs or devices

🖇 118. Split Testing / A/B Experimentation Bugs

Control vs variant users seeing conflicting data
Experiment flags persisting between installs incorrectly
UI breaking due to untested feature flags toggled remotely
Analytics not correctly tracking experiment arms

💥 119. SDK Conflict & Linking Problems

Conflicting versions of same SDK causing symbol collisions
Bitcode issues breaking 3rd-party SDKs at App Store upload time
Static vs dynamic framework linking problems
SDKs overriding global app behavior (e.g., appearance proxy, gestures)

🌐 120. Regional/Legal Compliance Bugs

Missing GDPR/CCPA flows causing legal exposure
Geo-restricted content not blocked properly
Legal text or tracking consents not translated correctly
Crash or block on region-based API calls (e.g., China-only features)