Carved Shelf Error

I also found a bug, put 8 books with a pen and 1 signed book in the autostack and put a carved bookshelf in front of the autostack when the autostack is activated, 1 signing book will fit in the first cell and 8 copies of books in the second cell. I found out about the error when I was making a mechanism that made copies of books. (I'm sorry, I'm writing this from a translator)