The bookmark rendition options are not selected in Vault Admin --> Settings --> Rendition Settings.
However, the bookmarks are created in the viewable rendition.
This is working as designed. When no option is selected, then bookmarks for any styles with Style Type Paragraph or Linked and Outline Level 1 to 9 are generated by default. In addition, the bookmark expansion level does not limit the number of bookmark levels generated, instead, it is the default number of levels expanded in the document when opened.
Vault Help Documentation: Bookmark Support