[cybmole]

can you test with other books ?

if you plan to do this often, I suggest you convert to epub with heuristics on, get hold of the sigil program & use that to open / edit/save the epub as needed.

then convert back to mobi.

that is how I do all my kindle stuff & I can now get everything as I want it on Kindle ( but only after lots of help from others in this forum along the way )

that may seem long winded but the epub format is easy to work with and the free tools are very good.

there is just one more trick you can try. email the mobi+new cover book to your free kindle address - maybe when it goes via amazon the navigation will get repaired - bit of a long shot but does not cost you anything to try.