[DiapDealer]

The ScrambleEpub plugin is designed to introduce the least amount of structural change as possible. Still, it's not unprececented that a problem goes away post-scramble. My first suspicion would an image-related issue (since the scrambler replaces images with dummy ones).

EDIT: After glancing at the html, I have very little doubt that the source for this particular kindlebook was not an epub. That's probably a big part of the problem right there.