The Invisibility hides Villagers and Zombie Villagers' clothes and robes, making them are looked like that they wear nothing.

Steps to Reproduce:

1. Summon an invisible villager and zombie villager by using the commands provided below.

   /summon minecraft:zombie_villager ~-1 ~ ~-1 {NoAI:1b,ArmorItems:[{},{},{},{id:"minecraft:diamond_helmet",Count:1b}],active_effects:[{duration:-1,amplifier:0b,id:"minecraft:invisibility"}]}

   /summon minecraft:villager ~-3 ~ ~-1 {NoAI:1b,active_effects:[{duration:-1,amplifier:0b,id:"minecraft:invisibility"}]}

2. Switch to spectator mode and look at the villager and zombie villager.
3. Take note as to whether or not the clothes and robes of invisible villagers and zombie villagers are rendered in spectator mode.