ember-bootstrap: maximum-call-stack-exceeded

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  outerFormSubmitted: false,
  innerFormSubmitted: false
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
Inner form submitted? {{innerFormSubmitted}}
<br>
Outer form submitted? {{outerFormSubmitted}}
<br>
{{#bs-modal-simple
  onSubmit=(action (mut outerFormSubmitted) true)
  submitTitle='submit outer form'
}}
  {{#bs-modal-simple
    onSubmit=(action (mut innerFormSubmitted) true)
    submitTitle='submit inner form'
  }}
  {{/bs-modal-simple}}
{{/bs-modal-simple}}

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": "2.14.1",
    "ember-template-compiler": "2.14.1",
    "ember-testing": "2.14.1"
  },
  "addons": {
    "ember-bootstrap": "1.0.0"
  }
}