Last modified: 2011-04-30 01:20:54 UTC
On a Persian installation of MediaWiki 1.15.1 stable release, all needed categories are incorrectly listed in the needed pages special page and Special:WantedCategories is empty. http://tinyurl.com/wantedcat I'm reporting this in a rush, so I couldn't check to see what's wrong myself.
I should have clarified that this happens when a direct link (like [[:Category:Blah]]) is made to a non-existent category page. Probably, this can be considered a feature not a bug. Anyways, I felt it would be more rational to see it in WantedCategories rather than WantedPages.
WantedPages just counts redlinks to pages. Category pages are no different to other pages in that regard, and nor should they be.