Thread:NoWayThisUsernameIsAlreadyOwnedBySomeone/@comment-24335865-20150613194744/@comment-26143371-20150730152559

That's the same for me. I'm not sure about it, but I think it has always been like that.

On the one hand it isn't a bug, as the comments are simply subpages of the corresponding page's talk page. And the answers are subpages to those subpages. For the MediaWiki software page "XYZ" has a associated talk page at "Talk:XYZ" and vice versa. The comment module creates pages at "Talk:XYZ/@comment-&lt;username&gt;-&lt;creation date and time&gt;". MediWiki now thinks that "XYZ/@comment-&lt;username&gt;-&lt;creation date and time&gt;" is the associated page in the main-namespace. However this page doesn't exist, thus the red link.

On the other hand, the guy(s) who wrote the extension should have changed that behaviour to make the link more useful.