v2.15.0-beta.1 helper bug

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  lValue: 0.2,
  rValue: 0.3
});

helpers.add.js

import Ember from 'ember';

export function add([lValue, rValue]) {
  console.log(lValue, rValue);
  return lValue + rValue;
}

export default Ember.Helper.helper(add);

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

<p>Now, we're under ember v2.15.0.beta-1</p>

<p>If we pass value 0.2 and 0.3 as references: </p>

<div>
	{{add lValue rValue}}
</div>

<p>If we pass value 0.2 and 0.3 as primitives: </p>

<div>
	{{add 0.2 0.3}}
</div>

<p>Now, switch ember version down to v2.14.0 to see the differences.</p>

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "beta",
    "ember-template-compiler": "beta",
    "ember-testing": "beta"
  }
}