Title is a metadata field. Filename is what you see in Windows Explorer.
filename: "The Annihilation Score -- Stross, Charles.azw3"
title: "The Annihilation Score (Laundry Files, Book 6)"
author: "Charles Stross"
I've resent books from calibre, overwriting the previous copy. (I use a send template based on the original filename from Amazon, for consistency's sake.) Done like that, the Content Catalog does not get confused. Mere metadata changes get picked up.
The Catalog uses filename and ASIN to keep track of books -- you need to let the Kindle notice a book is deleted, before resending it with the same ASIN but a different filename.
And yet, all the time I slip up and resend a MOBI. The original DRMed *.azw file is still there, and gets replaced by a *.mobi -- confuses the hell out of the Kindle. Either you have two books with the same ID, or you deleted the *.azw and the Kindle didn't notice, which turns the book into a sort-of-ghost.
From calibre, select books, press "delete key", at prompt, select "delete from device".
Do NOT select "delete from library" or "delete from library and device"!