I've recently encountered GeoPDFs created by a surveyor that was in a projected coordinate system but without an assigned Datum.
![RTPL_AU_0-1721172964283.png RTPL_AU_0-1721172964283.png](https://community.esri.com/t5/image/serverpage/image-id/109912iAD31A8A76380208C/image-size/medium?v=v2&px=400)
Add the ability in Catalog to assign the correct coordinate system to the pdf so that it is valid BEFORE we add it to a map.