JEI_REI - AlmostReliable/almostunified GitHub Wiki
The JEI/REI integration features automatic hiding of non-dominant items.
When resources are unified, the dominant items become the owners of all recipes. The non-dominant items are pretty much useless then.
The integration hides non-dominant items so they won't show up in recipes anymore.
This also ensures that non-dominant items are not accidentally encoded in automated recipes for mods like Applied Energistics 2 or Refined Storage.
This setting can be tweaked inside the unify.json config with the hideJeiRei property which is enabled by default.