Riven Bug with W and Q

I'm a G2 Riven main and I've been experiencing bugs against Garen mostly. I'm not sure if it's a ping issue (I have 35 at most) or not but Garen has been Q'ing me while he is stunned by my W. I also flash 3'rd Q'd onto a garen and it didn't knock him up and he kept attacking me. Pls look into this. Thnx.