Describe the bug
models.1=2
nbt.1.equipment.head=raw:iregex:^(?=.*turtle_helmet)(?=.*diamond)(?=.coast).

Above is the properties file, this will change the model of a turtle helmet with diamond material coast trim.
Wearing the helmet on its own will not display the trim in any shape or form.
If you wear any kind of other armor it will display the trim atlas texture for some reason
Wearing a chestplate would result the model to not render entirely
In the image you can also see transparency issues being present on the helmet that is not worn by player

Example Pack
bitmezbuiş.zip

• Minecraft Version: [1.21.7]
• EMF version [latest from dev-blog] -fabric
• ETF version [latest from dev-blog] -fabric