Sometimes, the links that point to topics inside the document don't work in generated docx. When you click the link, you'll be redirected to the start of the document.
VSdocman assigns a bookmark to each topic. A link to a topic is then created as a cross-reference to such a bookmark. A bookmark name is generated from a member name using File Names settings. If you use default Numeric file names, the bookmark name will have a short numeric form. You can see it when you hover over the link.
If you, however, use Pretty file names, the bookmark name will be constructed from code member's full name and this can lead to a quite long bookmark name.
But MS Word has a limit of 40 characters for bookmark names. If you exceed that limit, you'll get the behavior described above.
Solution
Always use Numeric file names when you generate docx format.