Yesterday I was trying to finish the Dragonguard quest, I got to the mini boss that is at the Mask(Dragonguard Mask)and all I could use was Barb trap, Jabs, Blood Mist and Wall of Elements. I relaoded UI and and the problem was still there so I went back through the doorthat I came through then reloaded UI, went back to the fight and still the same problem. So I completely left the area by running ALL the way back then tried again and finally got through. If you notice the stamina might be the problem, maybe?