Reported on Steam:

Not Sure if Bug: Party Favors Turret Barrels Stack When Repeatedly Replacing

I'm not sure if this is a bug, or even an exploit really, but maybe it is useful information to somebody out there.

If you build the Party Favors turret, then repeatedly replace it with another turret then put it back, the barrel it spawns to start with will keep stacking onto itself. Theoretically, this could allow you to stack a crazy amount of burst AoE onto one spot. It isn't immediately obvious this is happening, but rest assured they are there.

Maybe useful for a boss or speed run strat or something?