Refresh doesn't work correctly with minimum-input-length attribute

Question

Ui-select-choices doesn't render option from refresh when deleting and re-inputting the same input with minimum-input-length.

I have an ui-select with minimum n characters.

1: Input xx...xx, it works normally.

2: Delete whole xx...xx or few characters (input length lower than minimum length) then re-input it (new input is exactly the same as old one), trigger refresh function and return result but ui-select-choices does not render anything.

Ui-select

  <ui-select ng-model="ctrl.number.selected"
             theme="bootstrap"
             ng-disabled="ctrl.disabled"
             reset-search-input="false"
             style="width: 600px;"
             title="Choose an number">
    <ui-select-match placeholder="Enter an number...">{{$select.selected.id}}</ui-select-match>
    <ui-select-choices repeat="number in ctrl.numbers track by $index"
            minimum-input-length="3"
             refresh="ctrl.refreshNumber($select.search)"
             refresh-delay="0">
      <div ng-bind-html="number"></div>
    </ui-select-choices>
  </ui-select>

Refresh function

vm.refreshNumber = function(index) {
    if (index !== null && index !== undefined && index !== '') {
      vm.numbers = [];
      vm.testData.forEach(function(item){
        if(item.id === parseInt(index)) {
          vm.numbers = item.data;
        }
      });
    }
 }

Working demo

Is it a Ui-Select bug? If not then what should I do?