Game Breaking Graves Bug

I read his passive,it said nothing about this aside from reduced/bonus DAMAGE. Similar but far more simple than the darius heal bug,Graves can proc on hit effects twice. Didn't test to see if on the same target. Since he does in fact attack multiple people,this may not be a bug but its so OP. Darius was able to heal more if a new person entered his Q while its dealing damage. Graves applies life steal(and for all i know every on hit) to every target hit,max 3. If this is a bug its another Yasuo kidneystone. If its not,well combined with his defense buff,Hes the Yasuo kidneystone of the botlane.