Armor Trim Issues

[turtle1230]

When using the shader, armor trims either do not appear at all, or pieces with armor trims fail to load properly, showing a purple texture instead.

Vanilla 1.21.3 (no texture pack)

Vanilla 1.21.3 with the FancyPants-master texture pack

Also tested on version 1.20.4, and the same issue occurs there.
Let me know if you need any further information or a download link to the world file for testing.

With kind regards,
Turtle