3D models via Resource Packs sometimes have parts Z-Fighting, ruining the model!

Some 3D models made via Resource Packs sometimes have a few or a lot of parts Z-Fighting, ruining the model.
The model looked correct in 18w44a and below, but broke in 18w45a and above.

 

What I expected to happen:
Having a beautiful model with no issues on every part that I have made, This is the case in 1.13.2

What actually happened:
The model has some or most of it's parts having z-fighting issues in 1.14 pre releases/snapshots, ruining the model's look.

 

Steps to reproduce:
1. Create a 3D model and put in your resource pack, Try some big parts and small parts.
2. Launch 1.13.2 to see a good looking model.
3. Launch a 1.14 snapshot/pre release to see some of the parts may get the z-fighting bug, ruining the model.