Unable to update computed property of controller from computed property of a service that has a promies

power-select]1. The options i pass to power select comes from a service. The option array has duplicate values which i try to remove in my controller. I have made a twiddle put since it ember-twiddle does not support addonss (ember-power-select) till now. I have modified it little bit Ember twiddle

The comment code in twiddle is what I have on desktop. This code works in tweedle but does not work on my computer.

Issue: dropDown value is not visible on template

    import Ember from 'ember';
    const {
      get,
      set,
      computed
    } = Ember;
    export default Ember.Service.extend({

      locations: computed(function(){
        var self = this;

        return get(this,'store')
            .findAll('store')
            .then(stores =>{
                let locs = stores.map(store => {
                     return get(store,'adminAreaLevel2') +" "+ get(store,'adminAreaLevel1')
            });
                set(self,'locations',locs);
          });

});

And the code in controller is

//Controller
import Ember from 'ember';
const {
  inject: { service },
  computed: { uniq }
}=Ember;

export default Ember.Controller.extend({
   dropData: service('my-service'),
  dropLocation: uniq('dropData.locations')
});

---

The power-select-code that I cannot include in twiddle

{{#power-select
      options=dropLocation
      selected=selectedLoc
      matcher=locMatcher
      onchange=(action "selectLoc") as |loc|}}
      {{first-caps loc}}
    {{/power-select}}
  {{/bs-form-group}}