Kennen Ult Does No Damage While Zhonya's Active

I was just playing a game as Kennen and realized that for some reason, my ult stops doing damage while Zhonya's is activated. I tested it several times in the game just to be sure, and every time I activate Zhonya's, the damage immediately stopped. Kinda sad since Kennen is one of my favorite champs and now I wont be playing him till this is fixed.