This also happened to me when creating my mobs in my adventure map. All the outer layer parts of player heads are projected downwards, sides, front, and back.
I hate how it says resolved yet its not..... why does it say that? This isnt a rare glitch this an every time occurrence with the mob watch the video......
I hope they fix this next snapshot, but I think they said 18w50a is the last snapshot of the year?