Even if you tweak the metadata in calibre to fix inconsistent titles/atohors, it won't 'break' sync/popular highlights. So no issues there either

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However, if you're out of Whispernet range, and you don't switch the filename of the notes file (.mbp) to match the new filename of your book, you'll lose your notes/last page read for that book (if you have any).
That may also force the Kindle to reindex the book.