Maybe it checks whether it must exist on it's hb, and it also picks up items
on it's hb, and maybe it picks up items first?

Or maybe minions are supposed to get prevent getting, so party are supposed to
kill minions. And btw that place doesn't go down when mob dies, it goes down
when time runs out.

Just seems like party was too stupid to not kill minions and should have lost
stuff because of it.