EDIT: Updated graphic to add a second example
In this book I'm using as a test case (Andrew Louth's The Origins of the Christian Mystical Tradition), one particular paragraph gets parsed as a heading and put into the table of contents, but it's just a normal paragraph like all the others. (Style: book_para). The fact that it happens to begin with a number (I've inserted page numbers in where they go in the printed book, but I don't yet know how to make Logos create a page index for my book) can't be the problem because there are other paragraphs like that which import just fine without being treated as headings. EDIT: And another normal paragraph that doesn't start with a number also shows up in the TOC a bit later.

I wasn't able to create a smaller document with just the a few paragraphs from around where that paragraph is to reproduce this. Let me know if you need me to email the full .docx file to reproduce it. It's a copyrighted text which I don't have the right to share electronically with anyone so it's a bit problematic, but if you could promise to delete it after reproducing and fixing the bug, I think that would be OK.