I have a book I was trying to do some cleanup on to get rid of random line/paragraph breaks. I converted the book from MOBI (that showed as KF8 in the viewer) to EPUB with no problem. I edited the EPUB and reimported it into Calibre. I then converted it to MOBI (that showed as MOBI in the viewer), but the formatting was off; it looked like it was just one long page. Instead of trying to identify the problem, I just converted it to AZW3 (which showed as KF8 in the viewer), and it looked a lot better. I went through the options a little more closely, and found the option to save MOBI in new (KF8) format. So I tried that. Although I'm sure I didn't change any of the options in the conversion screens, it looks to me like the line spacing is changed.
In the Calibre viewer, the EPUBs look the same up until the edits I made.
Any suggestions?
Before:
After:
