Renekton W bug

So I played two games as Renekton earlier this week and both games I noticed that his stun wouldn't stun other champions even though the animation goes off. First example is Vlad's pool, I would go up to him to try and harass with the free stun, the animation goes off but Vladimir takes no damage and pools right out of the stun. It wouldn't be a coincidence if it didn't happen for nearly the entire game and no it wasn't just a delay because I tried stunning him again, but he flashes the W and takes no damage and isn't even stunned. The SAME thing happens when Lee Sin would safeguard to an ally. The stun would go off with the animation sound and fury bar, but enemy champions would take no damage from it. This happened two games in a row while I was playing as Renekton so it clearly is a bug and needs to be overlooked.