I am playing in my friend's realm. It seems that since the previous update, whenever we enter the Nether or leave the game near our villagers, they despawn. I tried putting name tags on each of them but they still despawn. It is quite disheartening when you spend ages trying to max out a villager then they despawn.
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Thank you for your report!
We're tracking this issue in MCPE-21416, so this ticket is being resolved and linked as a duplicate.
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