Villagers acting eccentric and dissapearing

Put the summary of the bug you're having here

What I expected to happen was...:
I expected the Villagers to occupy more than one building in the village. I also expected them not to dissapear without a trace.

What actually happened was...:
In a peaceful mode survival world in a well-lit, walled village consisting of two large houses, a church, a well, a library, and a butcher shop, the preist and the librarian have disappeared without a trace. The other villagers crowd into the church and never leave it.
Steps to Reproduce:
1. Enter the bugged village.
2. Build a wall around it, place a ton of torches everywhere, and mine the bookshelves in the library.
3. Observe that two villagers seem to be missing.
4. Observe the cultlike behavior of the survivors.