Created attachment 160249 [details] Example writer doc. Version: 6.4.2.2 (x64) Build ID: 4e471d8c02c9c90f512f7f9ead8875b57fcb1ec3 CPU threads: 4; OS: Windows 10.0 Build 18363; UI render: default; VCL: win; Locale: en-GB (en_GB); UI-Language: en-GB Calc: threaded 1. Open the attached document. 2. Generate a pdf. 3. Open in Adobe Reader (but try other readers as well). Click on the "Bookmarks" icon to open the document tree. EXPECTED RESULT: All Headings should be visible in the tree. ACTUAL RESULT: Headings with text set in "Tools > Chapter Numbering > Numbering" do not appear in the tree. Only headings which are typed in by the user appear. In the example document, Heading 3 is not shown because the text was set in Chapter Numbering, but Heading 4 is visible because the text was explicitly typed in.
In fact the headings "Chapter N" are empty. The text belongs to the numbering. And empty headings are omitted in PDF export. Your heading needs a content, so add a blank, for example.