Notifications not properly rendering main wiki URLs in subwikis

I do not have the possiblity to build a test-deployment. But steps to reproduce should be:

1. Install Domain-based Wiki
2. Login as Admin
3. Create a subwiki
4. Login as an user (e.g. U1)
5. Go to Notifications > Settings
6. Set all Pages Notifications to ON
7. Go to the subwiki created previously
8. Click on Notifications bell and turn 'Watch this wiki' toggle to ON
9. Login as Admin
10. Create, update and comment a page on the subwiki
11. Create, update and comment a page as well on Main Wiki
12. Login as U1
13. Go to subwiki and observe the notifications list

Since the upgrade from version 13.10 to 14.6 and now also with 14.10, we have a problem with the display of notifications in subwikis.

Viewed as HTML one can see, that both, link to the wiki page and the profile, are generated as relative URLs.

(Example below reflects the image part.)

<div class="notification-description"> bearbeitet von <span class="notification-event-user" data-xwiki-lightbox="false"> <img src="/bin/download/XWiki/JWielsch/123_klein%20-%20Kopie.jpg?width=40&amp;height=40&amp;keepAspectRatio=true&amp;rev=1.2" alt="Johannes Wielsch"><span class="wikilink"><a href="/bin/view/XWiki/JWielsch">Johannes Wielsch</a></span> </span> <div><small class="text-muted">vor 1 Woche</small></div> </div>