Entity's head x rotation can't be changed

When you try to change a mob's rotation using /tp @e ~ ~ ~ ~ 0 the mob's head still looks up and down despite the command block outputting that the mob was teleported. Also this happens when updating the nbt data using entitydata @e[type=Zombie]

{Rotation:[1:0.0f]}

. This is very annoying when putting a model on a mob's head. If the model is offset on the y axis it moves a lot around the head. I have confirmed that you can change the direction the mob is looking but not up and down.

Edit: In 1.11 there is still the same bug. A mob with or without a NoAI tag set to 1 can not be teleported to a position where it will look up. You can only change the Y rotation of a mob's head and not the z or the x