This is an issue in Scrivener’s converter, where only the first Level 1 heading gets assigned the “Heading 1” style (and thus Word cannot outline without a styled heading). This applies to V3.14, and remains an issue in V3.2. There is a regression in Scrivener V3.2 in that the RTF (and as a result the Aspose output) now does not get Level 1 or Level 2 headings, only Level 3 headings and you can see the result in the Word outliner in the screenshot here:
[attachment=0]Scrivener DOCX Bug.jpg[/attachment]
The Scrivener project is available here: https://forum.literatureandlatte.com/t/compiling-to-word-with-styles/39428/2