[GAMEPLAY] Warwick ulting through charm

I was playing a ranked game as Ahri and there was a WW (Warwick) on the other team. Several times when WW would ult me I would predict it and try to charm him out of it. 2-3 times i timed it correctly and my charm would hit him as he started his ult on me. However, instead of stopping his ult, his ult would continue and i would be suppressed as normal. I'm pretty sure this isn't supposed to be what happens, but if it is, my bad for reporting this.