Garen polymorphed bug [GAMEPLAY]

So, I was playing a game as Lulu, when the enemy team's Garen started to charge after me with q, after I polymorphed him he managed to still use his q on me during my polymorph and ultimately killing me. Here is a link to the video if it doesn't show up in the link section https://www.youtube.com/watch?v=lT8Rsw1TjZ4&feature=youtu.be

(Might have possibly posted the wrong link by accident, hence why the link in the body is different than the link above, please use the link in the body).