Player log and relevant dungeon file attached. EDIT: I only realized after posting this I'm on an old version. Steam isn't downloading the new version though... So I can't check if it's still happening in the new version.
I basically copied an entire floor of an old dungeon where the problem occurred as a blueprint and then pasted it into a new dungeon to see if the problem persists. It does. There's a room I placed with a single snake and a chest set to spawn when all enemies are defeated, but the combat music does not play. This does not happen in another dungeon I have made, more recently than the older one I pasted from. Some element of the old dungeon is breaking the music?