[Ripplinger]

The epub itself has no references to widows or orphans at all. I've already opened it (and other epubs) to check that wasn't causing an issue. So it's using whatever the Kobo uses as default, which is probably 3 as you said. I've seen enough end of chapters to be pretty sure of that.

I don't mind the 3 for widows and orphans, but I do mind when it creates a new page for the last one sentence paragraph of 3 lines at the end of the chapter when there's still 4 lines remaining free on the previous page. I've seen that many times on the Kobo (and zero times on Sonys in almost 2.5 years, pretty sure Sony's default is 2 for widows and orphans).

But when it breaks up paragraphs mid-chapter leaving 3 lines on one page, then stops to continue on yet another page is much more annoying than the chapter end. I can live with the chapter end, even though it still shouldn't be happening.

Edit: Apparently the software doesn't always listen to the 3 widow/orphan defaults either. I just hit the end of a chapter where only 1 line was on the last page instead of the usual 3. Nothing different in the stylesheet to cause it.