Translucent items render through the head of players with a translucent item equipped on their head with "Improved Transparency" enabled

With the “Improved Transparency” setting turned on, translucent items render through the head of players which have a translucent item equipped on the head slot. (This may also affect items in other slots, but I wasn’t able to test that)

Steps to reproduce

Make sure you have the “Improved Transparency” setting turned on.

Give yourself a stained glass block with this command:

/give @s minecraft:white_stained_glass[minecraft:equippable={slot:head}]

and equip it. Next, summon a mannequin with a stained glass block on its head and in its hand:

/summon minecraft:mannequin ~ ~ ~ {equipment:{head:{id:white_stained_glass},mainhand:{id:white_stained_glass}}}

Go into 3rd person and you should see the glass block on the mannequin’s head and in its hand through your head. Also, if you hold a stained glass block in your hand, it should also be visible through your head.