Faculty can't find their books in a Google search

Hi all! A faculty member reached out to me about not being able to find their books, Spunti: Italiano intermedio 2 and Spunti: Italiano elementare 2, in a Google search. I confirmed both book’s visibility are set to public, the attributes are public, the settings are the same as a book that does show in Google, and both show in the Pressbooks Directory. I’m not sure what to look at next. Any ideas?