Not sure this problem has been reported for Xbox or not but its happening here. I had a building with 5 villagers in it. 2 farmers (level 3), 1 librarian (level 1), 1 Fletcher (level 2), and a weaponsmith (level 2 I believe). I walk into the building and boom *they all have vanished into thin air. Including the cat that was there too. * It is quite frustrating to see your mending villager that you spent over 10 minutes trying to get that specific trade to vanish into thin air. Now the celing was open, but the walls were high enough to keep any zombies out which are the only danger to them. But there's no way that could happen because the walls were too high for them.
I am pretty sure I went inside the building when I loaded in the world today and saw them all there. I then went over to complete the roof to a storage shack which I would say is about, oh... About 25-30 blocks away. I then finished what I was doing and then went in to trade. Low and behold, theyre gone.