More often than not - mobs going into anti-exploit seem to be caused by path-finding issues where the mob seem to be on a different vertical plane than the player. So - when you experience it. Here's a few tips to get it killed regardless.
1. Check the environment around the mob. Is there a different ground type or a different ground height that differences you from the mob. If so - move onto the same ground as the mob.
2. If there's any objects near the mob (crates, campfires etc.) try to jump on top of them (and if that is not possible - jump close to them and strike in the air).
3. And finally - if you can't find any terrain differences that causes the exploit - try standing on top of the mob and jump constantly. If you are a melee class you can jump and strike in the air - if you're a ranged mob - you're not as lucky I'm afraid.
In example - all the Annuminas camp-mobs that always go into anti-exploit can be killed by some crazy jumping.
Of course - it would be better if there were no mobs in anti-exploit. But that's not gonna happen, so remember, anti-exploit is always caused by path-finding issues (the mob's ability to find its way to you), and can more often than not, be corrected by the player.