This happened to me last night. My Katina song on Lylat (repalces Break Through the Ice) started screeching mid-song (around the loop point) and switched over to Convenience Store, which replaced the Yoshi's Story Ending theme. It might have to do with improper looping AKA the loop point is not a multiple of 14336.
That can't be. I loop brstms not following that rule most the time. I would've had that in one of my songs.