[DoctorM]

Searching because of a similar issue, I did come up with a fix that I wanted to share.

I've found that AZW3 books with formatted text on a background of pictures don't display on any of the Android apps I've tried. Converting with Calibre2 to pdf does cause formatting issues.

I've tried a lot of changes even mimicking my method and I can't get it to work.
Theoretically, when converting you can go to the pdf output, select the page size and margins and do the same thing I'm about to describe... except it doesn't work for me.

Instead, I opened the book for viewing in Calibre. Then I selected print to pdf. I set the page size to A4 (in my case) with 1" margins on all 4 sides.
The output was a perfect pdf duplicate.

Using the default Letter size does have the text properly configured, but the pages are too long and the bottom inch comes up on a second page.