[GAMEPLAY] Pantheon W doesn't stun!

I played a game as Pantheon, i used my W alot that game and i noticed that sometimes it didnt stun at all. Its really frustrating when that bug can effect a whole games result. It happend twice that game. Once were when Darius pulled me in with his E while i W him at the same time. His E didnt pull me and my W didnt stun him. The second one was when i chased Warwick and my W just simply didnt stun. There were no attacks at the same time, no spellsheilds or black sheild. This aint much proof that the bug exist and i dont have any acreenshot or video but play a game with Pantheon and use your W alot and this bug might happend to you :)