I have a trading hall for villagers in which is pretty well lit up so there's no way for mobs to spawn inside or access my villagers. However, occasionally, the all of the villagers would simply disappear. This has happened twice so far. If one or two villagers disappeared, I would assume somehow a mob got to it but all of them disappearing twice is very odd and too coincidental.
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Thank you for your report!
We're actually already tracking this issue at MCPE-21416, so I will resolve and link this ticket as a duplicate.
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