A family of Microsoft word processing software products for creating web, email, and print documents.
Please disregard the suggestion to disable "Different First Page" and "Different Odd & Event Pages". Those options affect which headers and footers appear on specified pages, but they have no effect on page numbering.
That the sections "revert to start from page 0" is very odd. Aside from the apparent loss of the continuous numbering, I'd expect a section that doesn't continue page numbering from the previous section to begin at page 1, not page 0.
You should have section breaks only when a change in margins, orientation, page size, or number of columns is necessary, or when you want a different header/footer on the first page of a section (with "Different First Page" enabled). Delete all other section breaks. Instead of a section break to start a new page, you can open the Paragraph dialog for the first paragraph of the new page, go to the dialog's Line and Page Breaks tab, and check "Page break before".
If all else fails, delete the existing section breaks and insert new ones. The page numbering after each new section break should default to "Continue from previous section", and that should be stable through saving, closing, and reopening the document.