Minecraft wiki entry for Zombie_Villager, associated text: Zombie villagers never spawn with equipment in Bedrock Edition due to having rendering issues with armor on them.
Zombie villagers have a glitched design when using the programmer art Resource Pack. ‌[Java Edition only][8]
In Bedrock Edition, when a zombie villager holds a trident, the hand that holds the trident lowers.
The achievement ‌[Bedrock Edition only] Zombie Doctor uses the old zombie villager texture.