Villagers Disappeared

New snapshot loaded up. Villagers disappeared from my city. Created a new world to see how the snapshot affected the game in general and found some igloo villagers in a new world no problem. I rolled back my minecraft game and restored the world from the backup and the villagers are there.

So, something about this snapshot in particular corrupted the world I built up in that the villagers disappeared. I did not look for other side effects.