Game Mechanics: Charm problems, mobs despawning

[Clark]

I'm trying to figure out what happened. I had the frog king charmed and burned his LOT like I always did on live back in the day and on red99. The frog king was 36-38% when I zoned. Then I gated back to recharm and finish battle and he was despawned. Similar situation happened last night with tactician, but I can't remember the exact order of how it happened. With the mob regen kicking into effect there is no way any dots could have killed him trying to figure out what happened, and if you guys are aware of any current type of problem with charm/despawning. Thank you [You must be logged in to view images. Log in or Register.]