Issue With 3d Armor Model

I've created a model for a armor set, but it has a huge problem with the helmet and leggings

How It's supposed to look : https://imgur.com/BCWsogl

How the helmet actually looks : https://imgur.com/UJuIlSM

It's just the texture for the armor itself.

How the leggings actually look : https://imgur.com/QZXSRbZ

It's for some reason a mix of both?

How the Chestplate looks : https://imgur.com/iqAD9dT

The Chestplate is completely fine for some reason.

How the Chestplate and leggings look combined : https://imgur.com/sPeePPj

The Issue of the leggings gets combined with the chestplate

Any help to fix this issue would be appreciated.

Update 1 : Found out, This Happends to every single custom armor set model I make.