Villagers spawn from villages in biomes (like the desert, etc for example) the nbt data says that they're from the plains for some reason. :/ (PS - This also goes for Zombie-like entities when they infect a villager spawn form a village. The Zombie Villagers have the same problem, more less.)

Command (for 'normal' villagers): /data get entity @e[type=villager,distance=0..2,limit=1] VillagerData

Command (for zombie villagers): /data get entity @e[type=zombie_villager,distance=0..2,limit=1] VillagerData

Seed: -7562942002204730269

Coords: 672, 67, 24