Issue with Chogath's q

I had 2 instances in the same game when fighting a master yi as chogath where the master yi was able to dodge my q with his after my q animation had almost finished and should have already dealt damage and knocked him up. I'm not sure if this is a bug with the way that the animations are set up and when things trigger within the animations or weather this is an actual bug but it was extremely annoying watching my q go off and have a master yi walk right through it.