I think I fixed my own problem. I'm posting the fix here, for anyone else
that reads this and has the same problem. I went to the section following
the section break, and pulled up "Page Setup" from the "File" menu, and went
to the "Layout" tab, and found the section there to be listed as
"Continuous," which is why it kept changing it. I changed that to "New
Page," and it then quit changing my section break type back to "Continuous."
Hope this helps anybody else having this problem.

"boogaloo" wrote:

I am working in a very long document. I created it as a master document, and
then removed the subdocuments, so it is now one long document. I am going in
and creating section breaks (Next Page), and as I continue to work with the
document, it is changing my breaks to continuous by itself. How do I stop it
from changing my break types on its own?