[Gameplay] Champion pushed through a wall

I was playing as Tali and had just walled Anivia fron her escape. Anivia then cast her wall in front of her to block us out. I used my knock up/back and threw my e while Vi dashed into her and ulted. All of this seemed to create enough in the small area Anivia was locked into that she phases through the wall and on completing her ult Vi is on the opposite side of the wall in the Krug pit. If you look closely you can see I used my E to knock anivia forward not backward which may have knocked her over a wall. She appears as if she just flies right over the wall (Being a bird and all)