[Gameplay] Xin's Q Never Procing Knockup

I've been hearing about this bug every now and then but didn't think much of it until it happened to me in a ranked game. The title says it all. For some reason, there is about a 90% chance (not accurate) that Xin's Q will never trigger the knock up. The bonus physical damage is still applied from what I could tell. There really weren't any steps to triggering this bug other than playing Xin. If there is a larger post on this somewhere on which a Riot Employee has addressed the issue let me know. I can't say that this caused me to lose ranked games because there are many deciding factors. However, clearing, ganking, peeling, locking down, interrupting channels, etc were just made a lot harder. I hope to see this fixed soon.