@adam Same situation here, deleted or renamed they still hang around for a few minutes, probably until synchronisation is done, but that is not a big issue since it goes by it self.
This triggers are more of a issue, i am glad or not 
that you were able to reproduce this bug, i would be more happy if you did not so i could blame it on my fast fingers or extra bracket in the code, but 
its not. I did not have this issues with arduino library it poped up when transfered to mqtt.