Reference Fields and Hidden Markup - Help Authoring Site
If a reference field references something with hidden markup, it can screw up the hidden markup.
There is a problem with the way Word updates REF fields that causes the 'hidden EasyHelp Markup' to become visible. This is difficult to overcome with referenced headings because it is Word that is causing the behaviour.
However, we changed EasyHelp a while ago so that each topic heading has a bookmark that can be referenced. Turn on show book mark and you will see the [ ] marks in the Topic headings.
When making references, use the bookmark rather than a heading reference. This should correct your problem and is easier to maintain than the arbitrary numbers (that Word uses) when using heading references.
As far as the link itself goes you will find that word/phrase does not maintain the colour of the link text when updating. To overcome this you should change the field so that the /MERGEFORMAT (or German equivalent) bit is removed. Although the link will then come green rather than red it will work correctly when turned into a Help file.