Chiselled Bookshelves allow duplication when full

Right clicking on a chiselled bookshelf with any book type (while said chiselled bookshelf is filled with books) will result in the currently held book being duplicated. Additionally, this also causes enchanted books to stack, which they normally cannot do.

 

{}Steps to Reproduce{}
Fill a chiselled bookshelf with books. Doesn't matter what kind, whether they're the same, etc.

Right click on it with another book.

The book duplicates itself.