[Gameplay] KogMaw hitbox problem (or Malphite)

http://prntscr.com/cdg7xq

In this image, Kog'Maws body is clearly inside the amumu ult and should be tagged by it, but malphites arm is barely hit by it and he is stunned, yet Kog'Maw is not. I think this is a hitbox problem and NEEEEEEDS to be changed. Hotfixed or something.