Last modified: 2014-02-12 23:53:45 UTC
Recent persistent cookie changes for toggling mobile/desktop view cause bad behavior when a mobile view cookie gets set on a single-domain property (eg test.wikipedia.org). Since the cookie gets set at the top level domain, if you browse to en.wikipedia.org, you will be displayed mobile content from the desktop domain. Attempting to toggle back go the desktop view does not work, because currently MF only unsets the mobile view cookie if you're on a single-domain site.
Resolved with change-id I9676454ebd0c552ade4d375d3b1577c8f1568d7a
Assuming this is resolved since Arthur says so ^