attrbutes disappearing when observer on model

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  _test: function(){
 		var myModel=this.store.createRecord("myModel2",{});
    console.log(myModel);
    myModel.set("attr1",2);
    console.log(myModel._internalModel);
		console.log(Ember.get(myModel.constructor,"attributes"));
	}.on('init'),
});

application.template.hbs

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

models.my-model.js

import DS from 'ember-data';

export default DS.Model.extend({
  attr1: DS.attr("number",{defaultValue: 0,fromServer: 1}),
  attr2: DS.attr("string"),
});

models.my-model2.js

import DS from 'ember-data';
import myModel from './my-model'
export default myModel.extend({
  attr3: DS.attr("string"),
  _observesAtt1: function(){
    console.log(this.get("attr1"));
  }.observes('attr1'),
});

twiddle.json

{
  "version": "0.4.14",
  "EmberENV": {
    "FEATURES": {}
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.1.0/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.1.0/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.1.0/ember-template-compiler.js"
  }
}