There seems to be a problem in the newest snapshot where no villagers will spawn in certain villages.

Seed in which i first noticed the issue: -865306720498097

Right next to spawn there is a village in a plains/ roofed forest biome. (See attached pic for coordinates)

It appears to be able to spawn Iron golems and cats.

Re-creating the world does not make any difference, so it should be easy to replicate the bug.