variable.helmet_layer_visible = 1 not working

When wearing helmets on bedrock, it hides hair by default.

When making a texture pack, if you change the variable "variable.helmet_layer_visible" from 0 to 1

of the helmet.player.json, it normally stops helmets from hiding hair.

but after 1.21.2, it no longer does anything

 

before 1.21.2

 

after 1.21.2