This bug exist since Pocket Edition Alpha till now
Village always fail to generate in taiga, just because area is not enough to make village generate condition meet.
Taiga village only generate if plains village generate with well located in taiga biome, just like desert village that generate well in river resulting oak village in middle of desert.
Taiga village require condition that extremelly rarely to meet to be able generate successfuly. If successfully generated, taiga village can only generate at the edge of taiga biome, resulting few building in taiga biome while most building generated outside taiga biome. Making taiga village is only village that cannot generate in the middle of its biome.