I think John is on the right track here because it's probably not coincidence this occurs after bar 32. Check the Bar for End of Chorus (normally 32) and check the Ending measure in Song Settings if you are using a Tag.

However, I have had this happen to me on occasion, very rarely, and I have not been able to determine the cause. Usually, exiting BIAB and rebooting, then reloading BIAB will fix it so I suspect I've temporarily overloaded some internal resources of Windows. Another remote possibility is that the song file itself could have become corrupted. As far as I know, there is no way to see this yourself. The fix is to copy the chords and insert them into a new song, then the melody etc. and start over. Another possibility is to post a link to the problem song that you place somewhere on the Internet, such as Dropbox, so we can test it.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.