Similar to MC-234880 and MC-269460. The thorns enchantment does not work when entities are hit by snowballs or eggs.

How to reproduce:

1. /summon bogged ~ ~ ~ {ArmorItems:[{},{},{},{id:"minecraft:carved_pumpkin",count:1,components:{"minecraft:enchantments":{levels:{"minecraft:thorns":255}}}}]}

2. Throw a snowball at the bogged entity while in survival mode

Expected result:

You would receive damage from the Thorns enchantment.

Observed result:

You do not receive damage from the Thorns enchantment.