Thanks a lot for reporting this — you actually saved my main Unity package too, because the same texture turned out to be broken there.
I checked it right away and the problem was deeper than the export settings: the PNG file itself was corrupted. I rebuilt it from the PSD, re-exported it, and then re-embedded the textures in the FBX files to be sure everything is properly linked this time.
The files are updated. If you get a moment, please test it in Godot and let me know how it looks. Packs like this get better thanks to people like you — much appreciated.