I was able to reformat the document by a combination of using ctl-a, then reselect as default page style. This worked on half the document. The other half needed to be converted by going to the section header for that chapter, and selecting the default for the first and second pages, which were assigned different styles.
The paste to unformatted technique was noted. Its more a matter of not wanting to start over. My recommendation to libreoffice is if an operation like accepting a .docx document is going to create a huge mess, then warn or just donât do it. You want users to migrate from word? Donât whack them with a stick. But hey, that is my opinion.