Wikimedia Bugzilla is closed!

Steps to reproduce this bug:

1. log in to http://kk.wikipedia.org/ 
2. go to http://kk.wikipedia.org/wiki/Special:Preferences and change your language to English, German or whatever (don't mind the second language drop-down list, that is only the 'variant' option)
3. go to some normal pages (main namespace, categories or so) and note that the change was effective (all looks normal)
4. then go to some special pages (recentchanges, preferences or so) and note that your interface is the original language of the wiki again, and this behaviour doesn't change regardless of what you try (clearing cache, deleting cookies, logging in and out, using different browsers …).

Notes:
* I tested this with my SUL and with another test acocunt; it makes no difference. Also confirmed by other users.
* There are some more wikis with similar multi-language or 'language variant' support, e.g. http://ku.wikipedia.org/ but I wasn't able to reprocuce this issue there, so it seems that only kk.wikipedia is affected.