Ok. It seems like the FAB assets are now importing properly as long as people set up the conversion process correctly in the 3D preview and I was also able to find the RGB channel selection for packed texture maps (though that may have been there before and I was just blind).
I had this problem too (with the Fab plugin and other assets) and after searching for a few days I found out where was the problem.
Verify that you have “All” selected categories. In my case that was the problem, although I never used that dropdown in the past and I don’t know how I ended up not having “All” selected.
When exporting any game project, this error appears due to FAB
LogClass: Error: BoolProperty FFabAssetMetadata::IsQuixel is not initialized properly. Module:Fab File:Private/FabBrowserApi.h
LogAutomationTest: Error: LogClass: BoolProperty FFabAssetMetadata::IsQuixel is not initialized properly. Module:Fab File:Private/FabBrowserApi.h [log]
PackagingResults: Error: Unknown Error
I think 5.4 been out a while yeh! and thanks for answering the question! sorry you didnt, you just though a slagging was in order, what the hell do you know about anything i am working on!!!