It would be expected for Villagers to maintain any armour they were wearing upon zombification and revival, with dropping the armour being an acceptable secondary option, but instead it is entirely deleted from the entity.
It is also possible for villagers to gain armour and tools they were never given upon zombification, with said equipment being deleted upon revival.
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We're tracking this issue in MC-261666, so this ticket is being resolved and linked as a duplicate.
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