Bookmarks are created for paragraphs that have the OutlineLevel set (i.e. the predefined Heading styles).
If you create own styles, they won't have bookmark entries created automatically.
Or you can clear the OutlineLevel for individual paragraphs or for all Heading styles.
Here is sample code that creates a bookmark for a paragraph:
Code:
paragraph = sectionToc.AddParagraph();
paragraph.Format.OutlineLevel = OutlineLevel.Level2;
Set the OutlineLevel to BodyText to avoid bookmarks for headings:
Code:
paragraph = sectionToc.AddParagraph();
paragraph.Format.OutlineLevel = OutlineLevel.BodyText;
Better create a new style (e.g. "Heading1WithoutBookmark") and set the OutlineLevel for this style (to avoid setting it for every single paragraph).