Glad you found the .wav file button.

I am calling this a bug and have passed it on to the developers.

I am able to reproduce this strange behavior in seven steps.

1) Create a new song in BIAB
2) Use the Soloist Feature to add a RT (it will appear on the soloist track)
3) Generate and play all tracks.
4) Freeze the Soloist track
5) Save the file.

6) open the file in BIAB-VST
7) You will see that the Soloist track is now Midi. The rendered Audio for this track is from the midi. The RT on the soloist is gone.

Dan, BIAB2024, SoundCloud Win11, i7(12thGen), 32GB, 1TB SSD(M.2 NVMe SSD), 2TB Libraries, 1 TB(WD-Black), 2TB SSD(M.2 NVMe SSD)Data, Motu Audio Express, Keystation 61, SL88 Studio, Reaper