Warlock Drain mana bugged for player "Troggfather"

Hey my friend player "troggfather" has a bugged drain mana. even when I loggin it keeps bugging. what it does is it ticks for once and then stop cast, so the full duration channel NEVER happends. this is a kinda of SERIOUS bugg for uss cause we like to do 2s so this really ****s us up. This happends yesterday and we still havent recived any help.. would really be nice to have this fixed ASAP so we can do some more 2s before reset.

deleting cache does not help. Turning off every addons does not help, logging in on differencet computers does not help. this is something with warmane bugging ONLY this character