Twisted Fate, Yellow Card

I don't know if anyone else has expierenced this but for the first 10 minutes of my game my yellow card was not stunning anything, I hit the enemy master yi once and diana I was laning against 3 seperate times and absolutely no stun, it resulted in a hefty loss and a very fed diana since every time she dived me under turret with her ult I could not do anything, and I mean anything without his stun. I suggest you fix this asap as it pissed me off greatly