This should be fixed in 18.104.22.168.
I'm not sure what exactly was causing it to show up in the detail view controller, but I've added more aggressive logic for updating the navigation item.
As to what that indicator is...
In portrait mode (or any level of split screen), I'm collapsing the menu and basically making the app look like an iPhone, except that the inbox and achievements are still in the menu.
This presents a problem in that now you can't see when the totals update. In that case, I'm putting an icon in the top left corner to indicate that there is menu content. I was trying to be cute and put the indicator in the back button like the mail app, but the idiom doesn't really work here. In the next build, it will be its own separate navigation item that causes the menu to open: