Cannot get docx to insert section breaks #11482

The documentation for --top-level-division says:

In Docx output, this option adds section breaks before first-level headings if chapter is selected, and before first- and second-level headings if part is selected. Footnote numbers will restart with each section break unless the reference doc modifies this.

But this test.md document:

# Section One

Content

# Section Two

More content

When run through pandoc -f markdown -t docx --top-level-division chapter -o test.docx test.md produces a docx file with no section breaks. Does "section break" in this context mean something different than it does to MS Word (Selecting Insert -> Break -> Section Break)? Or am I doing something wrong with the way I'm setting it up?

This is Pandoc 3.9 installed via Homebrew.