Morgana Bug!

I was playing a game with the new team builder option, so I chose to queue mid with Morgana. About ten minutes in, I was 2-0 vs a Yasuo, going for my third kill, when I ulted. He dashed, while minions were holding me back, and escaped out of the circle, but the ult continued for about one more second while it shouldn't have.

Not sure if anyone was aware of it but he was pretty mad (: