GEODETIC_DATUM_ASSUMED_WGS84 - AtlasOfLivingAustralia/ala-dataquality Wiki
The geodetic datum was not supplied or was not recognised. Coordinates were supplied and are assumed to be WGS84.
Implications and caveats
There might be a shift of about 300 metres between different spatial reference systems, so depending on the spatial scale one is working at, not knowing the geodetic datum can make an otherwise perfectly serviceable record unfit for purpose.
Data custodian recommendations
geodeticDatum was provided, but
unrecognised, try to find the correct value in epsg.io.