Imho its basically mq2's problem as it gets an update of the person being there right before you fade, if they fade right after it never gets an update of you leaving the zone and as such leaves you there. With 5 accounts running, if I unload mq2 on one of them, fade the rest over and over again, I can't get any duplicates to show up on the one that isn't running mq2, so its definitely an easy way to know if somebody else is running mq2 if you both fade close to the same time.