Twice this has happened to me now, where I play a level and run into a powerful mob or mini-boss like an evoker or skeleton horseman. When i fought the skeleton horseman and evoker, I died while fighting them, and defeated them quickly after respawning. But, the boss music wouldn't stop playing for the rest of the game, even when I fought other bosses. The only way it stopped was when I finally beat the level and returned to camp. This isn't a gamebreaking glitch or anything but it is very annoying. This happened with the skeleton horseman mini boss and the evoker mini boss.