Xin Zhao's 'Three Talon Strike' not knocking up opponents.

I was playing as Jayce against a Xin Zhao jungle today, and he caught me in his jungle, so naturally, he jumped on me, and tried to knock me up. Here's the thing though, I DIDN'T get knocked up. I got stunned (or rooted, I didnt pay close enough attention), for a little under half a second. You can re-create this bug, by playing Xin Zhao, and trying to Q as many times as possible on things. It doesn't happen every time, but it seems like thtat, for a noticeable percentage of the time, his Q doesn't knock up like it's intended to. Pls, im not a xin zhao player, but this is a bug that should probably get looked into