Hello Bambi Vincent and welcome to the Apple Support Community.
Since the same Subtitle style works correctly elsewhere in the document, the useful distinction here is whether the separation is being created by the paragraph formatting itself or specifically during EPUB export.
“Keep with next paragraph” normally keeps a paragraph on the same page as the paragraph that follows it in Pages. However, a reflowable EPUB is repaginated by the reading app, so its page layout does not necessarily match what you see in Pages.
→ First, test the EPUB layout rather than changing the endnote style again:
• Make a duplicate of the document.
• Choose File > Export To > EPUB.
• Export one copy as Reflowable and another as Fixed Layout.
• Open both EPUB files in Books and compare the subtitle/endnote transition.
If Fixed Layout keeps them together but Reflowable does not, that would strongly indicate that the separation is occurring during reflowable EPUB generation rather than in the Pages document itself.
→ Then make one small isolation test in the duplicate:
• Leave the problematic subtitle and only enough surrounding content to reproduce the endnotes.
• Export that shortened document again as Reflowable EPUB.
If the problem remains in the reduced file, the result would be much more useful than repeatedly changing “Keep with next paragraph,” particularly since you have already found that the setting turns itself back on for the endnote text.
It may also be worth checking whether that Subtitle paragraph style is included in the EPUB table of contents. As a test only, temporarily remove that style from the table of contents in the duplicate document and export again.
If the pagination changes, that gives us another useful clue about how Pages is structuring that part of the EPUB.
At this point, we would not call this a confirmed Pages 15.3.1 bug without reproducing it, but the fact that the formatting is correct in Pages and changes specifically at the generated endnotes makes the EPUB export stage the part to isolate.
If the reduced document reproduces the problem in Reflowable EPUB, submitting that exact test case through Pages Feedback would also give Apple a reproducible example.
Could you tell us whether you are exporting as Reflowable or Fixed Layout, and whether the Fixed Layout test keeps the subtitle with the endnotes?
Please let us know.
🙏
Have a good day.
And one more thing…
Never forget to think different.
Important:
• Always make sure that your Apple devices have the latest available version of their operating system and that your apps have the latest available version so you can benefit from fixes and compatibility improvements.
• Pages 15.3.1 is the latest Pages version currently verified.
• Your Mac is listed as running macOS 26.5. The latest public macOS Tahoe version currently verified is macOS 26.6.2. You can check for it in System Settings > General > Software Update.
Useful links:
Create an EPUB book in Pages – Apple Support
Use footnotes and endnotes in Pages on Mac – Apple Support
Pages Feedback – Apple