Well I don't have a save from before the problem occurred. I don't know if it helps but I had the game on pause (space) for a really long time, but I am not 100% sure if this problem happened before or during the pause. I have played the game again on v0.12 (now I am on 1.0.0rc1) with the same data ...

Reviving an old thread here, but exactly the same thing happened to me. The music from the carnival in booty island loops endlessly in the background and any other music track plays normally on top of the booty track. "imuse stop all" fixed it for me but as I see it's a difficult bug to re...