Chips don't sync when item is removed

For example:

<div ng-controller="MyCtrl">
<chips data-ng-model="tags">
      <chip-tmpl>
           <div class="default-chip">
                   {{ chip }}
                   <span remove-chip="removeTag(data)"><i class="fa fa-times-circle" aria-hidden="true" style="cursor: pointer;"></i></span>
            </div>
      </chip-tmpl>
      <input ng-model-control placeholder="Select tags..." data-ng-model="tag" typeahead-on-select="onSelectTag($item, $model, $label, $event)" uib-typeahead="tag for tag in tags | filter:$viewValue" />
 </chips>
</div>

The problem is that if from the MyCtrl I remove the item from $scope.tags the chip dom element does not get removed as well, it remains. but if I remove the item clicking the cross the item syncs with $scope.tags model.

What I'm trying to achieve is not letting the users to select duplicated tags and reflect that in the displayed chips.