Soulless villagers who were zombified do not have AI if you leave the body while Players who were killed by zombies and zombified will still have AI.

Extra details: A similar issue happens when you cure a zombie piglin and then leave the cured piglin's body. it will have AI.

And as the cured body isnt undead, it isnt supposed to be moving around aswell.

Zombie villagers should now be fixed. Cured zombies moving around normally is a vanilla feature though.