Azir ult not giving knockback...

I was playing a mid game as Azir and an udyr charged at me. I used my ult the exact moment he stunned me and my ult went through udyr as well as my mid laner and did not knock either of them back. Of course, my ult went on cooldown.

I think this bug is caused when azir is stunned at the very same second he uses his ult.