Hi all, I'm seeing strange behavior with Special:RecentChanges (RC) when no cookies are set. I have five wikis. On three of them, *only when no cookies are set*, RC returns the header Cache-Control: s-maxage=10, must-revalidate, max-age=0 and intermittently returns stale results when refreshing, even forced refreshing, the page. On the other two wikis, I never see this problem on the other two wikis, which return Cache-Control: no-cache, no-store, max-age=0, must-revalidate and always return the current, correct RC results. Additionally, I'm watching varnishlog while refreshing RC on the 3 wikis that exhibit this issue and not seeing Varnish logging the requests, meaning the browser isn't even requesting the URL. There is no Expires header set for the 3 wikis, while Expire is set to "Thu, 01 Jan 1970 00:00:00 GMT" on the 2 wikis that work correctly. This problem seems to stem from the sendCacheControl() function in includes/OutputPage.php when $this->mEnableClientCache is true (false means it sends the no-cache, no-store header leading to correct browser results), but I don't know why the different wikis would have different behaviors. I've looked closely at the LocalSettings.php for all 5 wikis, comparing them carefully, and don't see any settings that might lead to inconsistent behavior. For what it's worth, all wikis are running MW 1.26.2.