[tmarsh1]

Here's my experience with this frustrating bug.

Removing the white-space:pre-wrap doesn't fix things.
It appears to be random. In smaller epubs, it seems ok, but I opened a larger one (90 pages) and these extra lines appear.
It's NOT css, it's NOT Pages.
The template generating these files in Pages is exactly the same, the files both have images, tables etc. I use styles to manage line heights etc.

I had the two clean checkboxes checked (on Save) which I think is what causes it.

I use Apple Pages as it supports intra-document linking, whereas Word on Mac does not (Bookmarks are a nightmare).

I basically can't pin this down to anything. The Sigil forums simply pour scorn on Pages, but I don't think it's pages.

It seems to occur randomly. I've unchecked Tidy too. And will report back.