Graves Autos can't hit Yorick Ghouls
There is a bug in the interaction of Graves vs. Yorick Ghouls. If Graves tries to auto a ghoul and it's not within ~3/4 of the range of his auto then Grave's auto will pass through the ghoul, dealing no damage. It appears to be a range-based bug as once you stand close enough to the ghoul your autos will start connecting.
I would grab a clip of it but I don't have a recording software and I can't save custom replays unless I want to sit through the whole game. Anyways, it can be reproduced with 100% accuracy.