For the record, I can reproduce this with BIAB Mac 2022.

If I export audio files to the same directory as the SGU, deleting the "_Render" component of the suggested base filename, everything in the mixer turns audio orange, track after track, as the export progresses.

(It's worth mentioning that the pre-export track parameters have not been destroyed and can be recovered by moving the WAVs and reloading the SGU.)

I realize this is behavior as designed but I can't say I find it appropriate. I'm just lucky I use subfolders for exports, as I always delete that "_Render" myself and am surprised I never got bit by this. It would seem more sensible to require a string like "performance_track" in files' names for their presence to have this confusing effect; as has been suggested, exporting heyjude.SGU as heyjude.WAV is really the obvious way to do that export.