FS#6696 - Instrument Music Doesn't Stop
When you are playing a song on an instrument, if you close out of the sheet rather than clicking the stop button, the music will continue to play. This seems to continue until you relog, and opening and using the sheet again doesn’t fix it, it will only make you play two songs at once.
I am not sure if other players hear this or just the player.
In my opinion, X’ing out of the music sheet should work just like the stop button.