I have some more understanding of this:
The problem is unwanted auto generated previews of a linked topic.
If this creates a link with a preview:
[But oddly, sometimes that does not happen]
In the edit window, the preview window shows this happening.
Then is prevents the auto generated link preview:
There is a <.> character preceding the link, <:> also works.
link offsets the preview window in another preview frame.
Where is the user's manual?