EPUB Export Fails to Break Correctly in Frontmatter in InDesign

Hi All, I have a book file with 67 files. When I first ran Export to reflowable epub, all the Frontmatter breaks worked. I had to make some changes within the book (other chapters) and now, although the paragraph styles have the Split box checked -- it isn't working. I've spent hours on this to no avail. I tried going back to the original print version and setting it up for epub -- but same issues -- nothing worked. This is only on the Frontmatter. The rest of the book breaks as it should. Same Paragraph Styles.

I've created many ebooks and never had this problem before. I checked back with my previous epub files and copied, again, what I did before -- no good.

What am I missing?

Windows 11, latest IDCC updates.

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