So... about Quinn...
From what I can tell, the harrier is a gigantic pain in the ass to deal with. It just does whatever it pleases when it pleases.
So, as a fix, why not allow it to toggle priorities?
Priority: Execute - focuses the lowest health target in the area. (Champions > minions, of course) Priority: Harrass - focuses enemy champions (if no enemy champions, focuses the highest health minion)
It seems like a simple enough fix, plus it would probably be something Quinn mains (however many even exist) would be thankful for.