Netherite armour does not lose durability points when the player is in lava

The bug

When wearing netherite armour, if the player jumps into lava, the armour does not lose durability points. I did not have unbreaking on the armour. When I summoned a zombie, it attacking me immediately damaged the armour.

How to reproduce

1. Put on a full set of netherite armour
2. Place lava and jump into it
3. The armour does not lose durability points