This is not due to a manual 'hard' page break. When I view the document in draft mode, there are no formatting icons except for a horizontal dotted line at the location of the page break. I cannot select or delete that line.
It also does not appear due to pagination settings. I selected the surrounding text, navigated to the Line and Page Breaks tab in the Paragraph window, and un-selected all of the Pagination settings.
I suspect that the problem might be related to the fact that I have Drawing Canvases and Equations at other locations in the document.