As of this week, I ran ruins of Mazzatun twice and found that during the fight with Xal-Nur, when he aoe fear, the ability to break free no longer works. I had full stamina and was still unable to break free at any point. I ran another group through and we found the exact same results. This results in you being unable to get into position most of the time to bash the boss so he wont charge another group member.