Let's assume I have opened a document which contains a link.
In the picture:
The document "ABDECKEN" is opened, containing the link "abräumen" (in the last line; links are green in my documents):
When I click on the link it leads me to the correct document (= "ABRÄUMEN"). But the document title above the text editor does not change. It remains the title of the page from which I am coming. That means the document title is not in accordance with the document that is actually opened:
This can be misleading, e.g. when looking at the wrong title above the editor you start to edit the wrong document.