Velkoz Ult AOE is not correct. Gameplay Bug

When fighting Velkoz, if you get behind him during his ult, hit ultimate can still do damage to you although he is aiming the complete opposite direction. Noticed this in multiple games when jungling as shaco, velkoz uses his ult on team mates, i deceive behind him but still take damage. Velkoz's ult should be strictly limited to whats in front of him, even if i was standing directly On him i should not take dmg.