why does LO insert page breaks after paragraphs, which don't show

Suddenly a fiction ms. I’ve worked on for months has started turning some paragraph breaks into page breaks. If I want a page to stay continuous, I have to delete the paragraph break (e.g. at the end of each line of dialog) & re-add it after the line jumps from the new page back to where it’s meant to be, on the previous page, following the previous paragraph. Since this has to be done one line at a time, & doesn’t solve the problem, it means basically I can’t edit the ms…

LO version? OS?
Problem may be caused by spacing settings in paragraph style definition. You may have inadvertantly change the style. Which style when problem occurs? Which one when not?

Problem happens on Mac (Yosemite 10.10.5) whether document is saved in .odt, .doc, or .docx. Style = Default Style, defined as flush L with .4 first-line indent, no # between paragraphs, no widow/orphan protection. “Keep para. together” settings make no difference, nor adding/deleting headers/footers, nor switching style to Text Body. After trying everything I could think of, I opened it on my old Lenovo (Windows 7) via Dropbox, made a “select all” copy in .docx & cleared formatting, & that seems to be working. But PC is where the ms originated, & W7 is too out of date to rely on. I suspect the same problem will recur when I move it back to the Mac.

Could you upload a reduced version exhibiting the issue? If you agree I’ll upvote your question so that you can attach the sample file editing the question.