You and other other entities (for example sheep) are able to push villagers out of there bed.

Server:
On relog they are laying for a moment in there bed but after few seconds they get moved back the place they were before relogging.

Singleplayer:
On rejoining world they just lay back on there normal place in bed, but if one is on top another, one dissappear.

Both:
When restarting if one villager is on top another one, one dissappears from the world.
From multiplayer: 

[17:32:01] [Server thread/WARN]: Wrong location! (-1, 0) should be (-1, -1), avl['Villager'/23, l='world', x=-2.50, y=63.69, z=0.50]

I have been able to reproduce it every time.