Villagers stuck as librarians

In a villager trading area, I have found that my villagers will not turn back into default villagers upon removing their lectures. I have never traded with them. The glitch is just their appearance and they have no librarian interface. However they will not turn into other professions or go back to default.

 

In the attached images it shows how one of the villagers cannot be traded with and just appears as a librarian.