While playing in my village, completely surrounded by fences and with enough lighting that nothing hostile spawns in, some of my villagers completely vanish.

I had three farmers in my village one game day ago, and now they're all simply gone. I've cured roughly 20 zombie villagers, and my village currently contains 7 villagers. There is nowhere they can wander off to get lost and no way there should be anything killing them.

Raiders cannot get into the village, and phantoms have not been spawning.