Root segment resolve block fails to execute on non-root segment refresh

[wingedfox]

$routeSegmentProvider
  .when('/', 'root')
  .when('/sub', 'sub')
  .when('/sub/sub', 'sub.sub');

$routeSegmentProvider
  .segment('root', {
    templateUrl: '/views/main.html',
    controller: 'MainCtrl',
    resolve: {
      Settings: function(Settings) {
        return Settings.load();
      }
    }
  })
  .within()
    .segment('sub', {
      templateUrl: '/views/sub.html',
      controller: 'SubCtrl',
//      resolve: {
//        Settings: function(Settings) {
//          return Settings.load();
//        }
      }
    })
    .within()
      .segment('sub.sub', {
        templateUrl: '/views/sub-sub.html',
        controller: 'SubSubCtrl',
      });

Here, when I navigate to 'root' segment its' resolve block resolves correctly. When I navigate directly to 'sub' or 'sub.sub' segment, I have to define the same resolve in 'sub' block, because 'root' resolve is never getting resolved.
It seems that the segment bound to '/' path are somehow broken.