The Bug

A few days ago I reported MC-265813 (Sunlight damages helmets worn by Wither Skeletons and Zombified Piglins)

At the Time I didn't realize how broken the Mechanic of Helmets worn by Zombies and Skeletons truly was.

It turns out Netherite Helmets can get damaged and break by the Sunlight even tho the Durability of Netherite Armor usually doesn't decrease by Fire Damage.

How to Replicate

1. Stand in Sunlight
2. Spawn a Zombie wearing an Iron Helmet:

   /summon zombie ~ ~ ~ {ArmorItems:[{},{},{},{id:"minecraft:iron_helmet",Count:1b,tag:{Damage:163}}]}

    
   → The helmet breaks since Iron Helmets are not immune to Fire

1. Spawn a Zombie wearing a Netherite Helmet:

   /summon zombie ~ ~ ~ {ArmorItems:[{},{},{},{id:"minecraft:netherite_helmet",Count:1b,tag:{Damage:406}}]}

   →  The helmet breaks despite Netherite Helmets being immune to Fire.