Summary:
In 1.20.20.20 Preview, zombie villagers now appear partially or completely invisible in the following resource packs (list may be incomplete):

• Steven Universe
• Adventure Time (Fixed)
• Ice Age (Fixed)
• Star Wars (Fixed)
• Super Cute (Fixed)
• The Nightmare Before Christmas (Fixed)

Steps to Reproduce:

1. Open a world with one of the resource packs listed above enabled
2. Spawn a zombie villager

Observed Results:
The zombie villager appears partially or completely invisible.

Expected Results:
The zombie villager should appear the same way it does in 1.20.1.

Screenshots:
1.20.40.23:

1.20.20.20:

1.20.1: