Thanks George for the update.
FYI, the current 2022 Band-in-a-Box, BiaB, for Windows build is 920. Build 920 is available
+++ HERE +++. However, in this instance build 918 is likely not causing your issue.
Speaking VERY broadly BiaB can consider EVERY song project audio track to be an Artist Performance Track or APT for short. If the song title is in the audio file name, there is a good chance BiaB will consider the file an APT.
Editing and saving a Realtrack creates an APT. BiaB then recognizes the APT.
Regeneration of a RealTrack changes track data. There is no audio created (the audio exists in the RealTrack folder) so there is no APT opportunity.
When using the BiaB audio editor, Ctrl+Z removes edits. A second Ctrl+Z should restore the RealTrack.
One way to avoid an audio file becoming an APT is to rename the audio file to something that doesn't include the song title. For example "RT1553 guitar, lead, sw16 185 MySong.WAV" could be renamed as "lead guitar".