Librarian villager trades change from previous in 20w09a.

I had a world in the snapshot 20w09a and recently updated it to 20w10a. I checked my librarian villager who had the mending book trade and it switched to loyalty.  My other librarian villagers' trades changed but it only seemed to be what enchant the book they were selling had. My shepherd villager's trades did not change, just the librarians.