Forum:Question about the Mana Shield for mages

I have a Mana shield which in its discription it says:" casting the shield will absorb 60 damages in guild battles and guild monster fights (lat for one hour). However, in action after the first time the shield has absorbed the damage, it will be removed even if it is only 2 minuites after its casting. In monster fight you need only one stamina to cast the shield, so although it is very trouble some to go back and forth between your team and the Monster team to cast the shield each time, atleast it worths the less damage done. In guild battles however, you need one token to cast the shield and it is gone soon after you cast it. Counting the lower number of battle points awarded for casting the shield, it makes it pretty much worthless. Is this how the shield was suppose to work, or has there been a fluke?