[InsainArcaneBirdbrain]

This one's been around for a good while I think. In the preferences menu, if you set it to custom music only, it works as intended until the player completes a battle. Once a PvE or PvP fight concludes, the music goes dead, and stays that way even on further battles that you engage in until you relog. Easily testable if you use a marching band with a custom theme set, and finish a fight.