Yes, this is the apparent correct behaviour.
If you look at /etc/config/general, you'll see your site as the update server.
To put it back, there are a few options:
1. Have orange mesh change that setting back to the open-mesh server. There isn't a setting in the orange-mesh Network page, so you'd have to edit checkin-batman.php and add it.
2. ssh into the node and change it in /etc/config/general.
Note that if you change it on the node and open-mesh still has the alt server set, it will send your node back to the alt server after the first checkin.
3. edit /sbin/update on the node and have it checkin to 2 places! If you checkin to open-mesh (wget with /etc/update/update.arg) and ignore the response, you'll still see the pretty graphs on open-mesh.
Hope this helps.
Another thing to note is the upgrade server does not get changed automatically when you use orange mesh, so your nodes will still try to upgrade based on the open-mesh site.