Volatile Computed Bug

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  init() {
    this.set('prop', 1);
    this.set('computedProp', 1);
  },
  
  get prop() {
    return this._cachedValue;
  },
                                       
  set prop(value) {
    this._cachedValue = value;
  },
  
  computedProp: Ember.computed({
    get() {
      return this._computedCachedValue;
    },
                                       
    set(key, value) {
      return this._computedCachedValue = value;
    }
  }).volatile(),
  
  actions: {
    incrementProp() {
      this.incrementProperty('prop'); 
    },
    
    incrementComputedProp() {
      this.incrementProperty('computedProp'); 
    }
  }
});

templates.application.hbs

{{outlet}}

<div>
  <button {{action 'incrementProp'}}>ES5 Getter</button>{{prop}}
</div>

<div>
  <button {{action 'incrementComputedProp'}}>Computed</button> {{computedProp}}
</div>

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}