Resource pack gloves don't show in first person mode

When you use a resource pack to make chestplates have gloves/gauntlets (Or anything that goes on your arm/hand) it doesn't show up on your arm in first person mode.
How to reproduce:
Download or make a resource pack that adds gloves or gauntlets (Or anything that goes on your arm/hand) to chestplates.
Install it.
Enter a world and put on a chestplate.