The Bug:
The legs of baby zombies go through the heads of entites they are riding.
Steps to Reproduce:

• Summon a baby zombie riding a skeleton.

• /summon minecraft:skeleton ~ ~ ~ {Passengers:[{id:"minecraft:zombie",IsBaby:1b}]}

• Look at the baby zombie's legs.
• →  Notice how the legs of baby zombies go through the heads of entites they are riding..

Expected Behavior:

The legs of baby zombies would not go through the heads of entites they are riding.
https://bugs.mojang.com/secure/AddComment!default.jspa?id=456785