Strange mapping WordPress MultiSite

Hi team, I have installed a wordpress MultiSite for http://www.wingsforbusiness.com. One of the sites is http://www.agooddeedtea.org, which maps to agooddeedtea.wingsforbusiness.com.

Something strange happens. The urls http://www.agooddeedtea.org and agooddeedtea.org (so without the www.) do not map to the same webpage. You can see it in the menu.

http://www.agooddeedtea.org is the most actual page. agooddeedtea.org seems to point to some stale version. Every update I perform on the homepage is NOT shown on agooddeedtea.org. Even if I which the homepage it is not displayed. Whatever I do, I cleaned all the caches and restarted the VPS.

If you use agooddeedtea.org?x=x it does go to the correct version. Also all other pages, like agooddeedtea.org/content show the correct information.

Have you any idea what is going on here? The problem did not appear before we used MultiSite. Any answer, or direction for further troubleshooting is most welcome, as this problem is buggering me now for 3 fulltime days.

Thanks for your help! Sophie