Properties on nested objects in ember doesn't fire if the object key was in PascalCase

This is a why this happens question

like the title suggests, if I have a PascalCase object key, custom properties on it won't fire when the model properties changes

Here is an example

App.CustomModel = Ember.Object.extend({
  workProp: function() {
    return this.get('work.val');
  }.property('work.val'),
  wontWorkProp: function() {
    return this.get('WontWork.val');
  }.property('WontWork.val')
});

App.IndexRoute = Ember.Route.extend({
  model: function() {
    return App.CustomModel.create({
      work: {
        val: 'Bar'
      },
      WontWork: {
        val: 'Bar'
      }
    });
  }
});

and the hbs

<h2>This works</h2>
<div>
  {{model.workProp}}
  {{model.work.val}}
  {{input value=model.work.val}}
</div>
<h2>This doesn't</h2>
<div>
  {{model.wontWorkProp}}
  {{model.WontWork.val}}
  {{input value=model.WontWork.val}}
</div>

Fiddle: http://ift.tt/1EUNhVl

Any idea why?