Thread:Talk:MediaWiki/Why it ask me whether to 'clear the cache of this page' all the time

I setup the media wiki with SimpleSAML extension ready. I can log into the wiki. However, every time when the cookie is expired, the page will ask me to clear the cache with following messages. Is there something wrong in settings? I went through http://www.mediawiki.org/wiki/Manual:System_administration but didn't find obvious variable to make it right. Idea?

Clear the cache of this page? [OK button] Purging a page clears the cache and forces the most current revision to appear.