I did experience something similar in BIAB2021. Occasionally after a regeneration of a complete song, *all* chords were angry red rests.

This seemed to happen only when I had tricked BIAB into handling eights, by setting the tempo to double the intended, and then set all/most realtracks to half tempo.

I got the impression that the file had become corrupted.

This error hasn't happened now with BIAB2022. Yet ...