Horse texture mixes with diamond horse armour texture

Put the summary of the bug you're having here

What I expected to happen was...:
The horse texture would be hidden by the armour

What actually happened was...:
The horse texture clips through the armour and it mixes with the armour texture

Steps to Reproduce:
1. tame a brown horse with black dots
2. put diamond armour on it
Also I use fabulously optimized but i dont think that would cause this issue