I'm only asking as I've tried to simulate this with different plugin commands for the same event, but I think there is a bug, as somehow the sound refuses to start until I enter a menu, and stops immediately once I do any action.
EDIT: as in, I tried making the change in your "bard tavern loop" by putting two different plugin commands separated just by a single "wait" command (10 frames, like you did) - that apparently bugs the engine.
Any news about adding support for multiple same type sounds overlap? Does it support the Subfolder update, by chance?