Mobs are immune to armor stand Thorns

The bug

You can make a armorstand and put armor with thorns on it, and when you hit it you get damaged. However, zoglins or any other mobs don't take any damage.

To reproduce

1.Run this command in a command block to spawn the armor stand:

/summon armor_stand ~3 ~ ~ {equipment:{head:{id:diamond_helmet,components:{enchantments:{thorns:3}}},chest:{id:diamond_chestplate,components:{enchantments:{thorns:3}}},legs:{id:diamond_leggings,components:{enchantments:{thorns:3}}},feet:{id:diamond_boots,components:{enchantments:{thorns:3}}}}}

2.Spawn a Zoglin and observe what happens.

Observed results

Zoglin cannot take damage.

Expected results

Zoglin take damage.