It does seem to be a more general problem though.
I recently added Nigella Lawson's Kitchen. When I click on the book from my bookshelf, I get "0 notes". If I then click on any recipe from the book and then on the link to the book in the recipe, all of a sudden it has 77 notes!
Have you changed anything about the notes lately?
And if I wonder if a particular recipe has notes, it does not really help to know that it is somewhere in my 779 notes - if it exists at all.