Last modified: 2008-08-19 01:45:16 UTC
When http://en.wikipedia.org/w/index.php?title=Special%3APrefixIndex&from=User+talk%3AThingg&namespace=0 is clicked, the results include a link to http://en.wikipedia.org/wiki/User_talk:Thinggar , which is not a subpage of http://en.wikipedia.org/wiki/User_talk:Thingg .
This is how AllPages works. It's not just displaying subpages, but pages that _begin_ with that name. As Thinggar is indeed prefixed by Thingg (+ar), the behavior is correct.