Well, shoot. SetDmapEnhancedMusic() writes 255-character filenames, but DMaps only have room for 55 characters... It's not only overwriting the subscreens, but almost 200 disabled items, as well.
I don't think there's any way to work work around it, generally. If you only use one subscreen in the quest, deleting all the others should work. If you only set the music for DMaps using the same active and passive subscreens, putting those first in the list should work. For any cases other than those, it's just going to have to be fixed.
