Just loaded up my box group and am still having the same problem with sticking. My MT uses a macro for pulling then MQ2Melee for combat. Only other melee in group uses MQ2Bot. Neither will stick until I unload/load MQ2Melee while in combat.
I do notice that when I stop, then start my pulling macro, which involves a couple of unloading/loading MQ2Moveutils operations, that the problem returns. Then, when I do a Mq2Melee unload/load while in combat everything works fine again (in fact, I have cranked that into my macro now to account for this issue).
I can't explain why my other melee running MQ2Bot won't start sticking until I do an /MQ2Melee unload/load, but once I do it, they run fine indefinitely.