Well when it hangs up it has a corpse targeted. I can only get it to hang when trying to keep multiple mobs in camp. I play my puller manually and jut keep 2 to 3 mobs in camp, I just notice my warrior/tank hanging on a corpse when trying to switch to the next mob, but once I manually target 1 of the adds he takes off again. I am not sure if the ID is not getting properly dropped from the adds array or not. I am just not sure why a corpse is being targeted. I have seen this happen a couple of times when on autopilot and a mob will add from respawns. It just has something to do with mobs adding after cambat has started and there are more mobs in camp than when combat started.
But after pulling for a few more hours it never hung after the fix. I did notice another funny behavior, for some reason my tank would keep sitting to med then stand right backup, now when his stamina would get really low and med everything was fine, but if his stamina was close to his medat number, he would sit, stand, sit, stand... till next mob was in camp then he would med like normal.