Gameplay: Vel'Koz ult doesn't move

While not a game breaking bug, it is quite annoying for someone who mains Vel'Koz and spams him in ranked, to sometimes have my ult go off, but not be able to turn/move it. Sometimes, the exact occurrence rate is unknown to me, my ult goes the full duration, and full damage, but it just won't move. This happens about...if I HAD to guess, 1/30 times I ult. Maybe more frequently? I've only seen it on Summoner's Rift, but I don't play many other maps. I just feel so dumb standing there with my ult in one spot while my team is trying to fight, lol. Again, is it game breaking, no since it's not that often. But if someone could just maybe take a peek very quickly and see if it's something minor in coding and what not? I don't know how long the process takes but if it's something small then it would be greatly appreciated!