I have had two villagers disappear out of nowhere that were in my trading hall. Both of them were in 1x1 areas that they could not get out of, and it is highly secure with no way of mobs being able to get in. I've never experienced any kind of disappearing villager bug until this most recent version. These villagers couldn't have despawned from being too far away from their village, as I have a villager breeding area with many beds that is not even 10 blocks away with many other villagers also in it.