I've been encountering this bug more, as im sprinting through delves trying to get skyshards, and end up in combat. it seems when im low on stam, none of my skills work, even skills like blockade which is entirely magicka cost, and im full magicka. I cant cast the skill until I drink a potion. trying to cast it, my char just twitches, and tries to do animation, but it cancels out, and none of the dmg happens, but it uses magicka resources.