Word to epub bookmark display is incorrect

I have a Word document and I find that when I convert it to ePub format, the bookmarks are not displayed correctly.

void Main()
	var doc = new Aspose.Words.Document(@"C:\Users\54390\Downloads\f92690fd45a94a7e8ec7bdbdf747a9b4.docx");
	doc.Save(@"C:\Users\54390\Downloads\output.epub", Aspose.Words.SaveFormat.Epub);

Version info:

Aspose.Words for Net 23.2

The demo file:

f92690fd45a94a7e8ec7bdbdf747a9b4.docx (4.7 MB)

The screenshot:

We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.

Issue ID(s): WORDSNET-25107

You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.

It looks like your original document was create by concatenation of several document with ImportFormatMode.KeepDifferentStyles that leads to a lot of Heading_X_Y styles created in your document. Aspose.Words included only Heading_X styles into the EPUB navigation panel. So as a temporary workaround, you can concatenate your documents with ImportFormatMode.UseDestinationStyles mode. In this case duplication Heading_X_Y styles will not be created and navigation panel should be build properly.