[GAMEPLAY] Graves is Drunk

I am a Mac user so that may have something to do with it and at least you can look into that specifically. What happens is when I'm CS-ing with Graves (and only Graves) his buckshot will not shoot in the direction I click, sometimes not eve close. He never hits the minions I click on (yes, I know his AOE AA hits many) and last night he got way out of hand and shot to his left at nothing when I clicked a minion. IDK if he's shooting things that are not there or he just cant hit a minion. I thought it was a weird lag at first, like I had clicked the minion and it moved then he fired, but my ping was fine and everything else working. Same thing with champions, Graves won't hit them with AA all the time. Or I will visually hit them but they lose no health. Even if Im standing on them. I mean, is this a bug or do I just not understand this man? Thanks!