Interesting, I have exactly that problem. I created a redstone-block-based iron farm (16x16x8) and placed 16 doors on each side with the proper number of opaque blocks on top to make a village. For a time it worked and iron was produced, then one day I log in and all my villagers are gone. I replaced them, but now no golems spawn and all the villagers are on one side of the farm and never go anywhere else.
Interesting, I have exactly that problem. I created a redstone-block-based iron farm (16x16x8) and placed 16 doors on each side with the proper number of opaque blocks on top to make a village. For a time it worked and iron was produced, then one day I log in and all my villagers are gone. I replaced them, but now no golems spawn and all the villagers are on one side of the farm and never go anywhere else.