What the hell is going on with stamina?

Its been happening since the last update..

Was is a duel, with my Warlord...

My stamina bar was completely full...... I gb my opponent, threw him into a wall and hit him with a single heavy.... and was completely out of stamina.... WTF?

Same happened with raider....

I was in a dominion with my zerker earlier...... activated revenge.... and had no stamina at all for its duration... was exhausted...... again... wtf?

What have you done Ubi?