[Gameplay] Diana E can knock champions away?

As simple as it sounds. This is very rare from what I've seen, I can only recall happening twice out of hundreds of Diana games I have played. The first time it happened was months ago, and if I remember correctly I was against an Anivia. I didn't report it that time. This time I was against a Ryze.

https://www.twitch.tv/videos/206595087

I'm about 100% sure this is not how Diana's E is supposed to work.