Villagers all spawn as similar types. They usually spawn in accordance to house type, however they now spawn as all the same or similar. I was looking for some Villages, when suddenly I noticed that the Villagers were all Farmers! I went to another Village and lo! they were all Blacksmiths. In another they were all Librarians. How to spot this bug:
1) Find Village
2) Check that Villagers are all the same or nearly, regardless of house type.