Setting computed to same value doesn't trigger recompute

controllers.application.js

import Ember from 'ember';

let uuid = 0;
const { get, set } = Ember;

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  num: 5,
  newUUID: Ember.computed('num', function() {
    ++uuid;
    return uuid;
  }),
  actions: {
  	setNumToSame() {
      set(this, 'num', get(this, 'num'));
    },
    setNumToDifferent() {
      set(this, 'num', get(this, 'num') + 1);
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
wont trigger recompute<br/>
<button {{action 'setNumToSame'}} >Set num to same value</button><br/><br/>
will trigger recompute<br/>
<button {{action 'setNumToDifferent'}} >Set num to different value</button><br/><br/>
{{newUUID}}
<br>
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}