Having some issues with Ember data and specific routes

Problem with Route

// app/routes/sessions.js

export default Ember.Route.extend({
  model: function(){
  	return this.store.find('formatted-sessions', {event: this.modelFor('event').get('id')});
  }
});

// app/models/formatted-sessions.js

export default DS.Model.extend({
	formatDay: DS.attr(),
	thisSessions: DS.hasMany('session')
}); // Does not make a difference what is inside the model, same error

// Makes a call to http://127.0.0.1:8000/formattedSessions?event=528d909d25afafac19000001

// Response from API

{
  "formatted-sessions": [
    {
      "formatDay": "Wednesday, December 4th 2013",
      "thisSessions": [
        "52c8af1ae45da0643500004c"
      ]
    },
    {
      "formatDay": "Thursday, December 5th 2013",
      "thisSessions": [
        "52c8af1ae45da0643500004b",
        "52c8af1ae45da0643500004a",
        "52c8af1ae45da06435000049",
        "52c8af1ae45da06435000048",
        "52c8af1ae45da06435000047",
        "52c8af1ae45da06435000046",
        "52c8af1ae45da06435000045",
        "52c8af1ae45da06435000044",
        "52c8af1ae45da06435000043",
        "52c8af1ae45da06435000042",
        "52c8af1ae45da06435000041",
        "52c8af1ae45da06435000040",
        "52c8af1ae45da0643500003f"
      ]
    }
  ],
  "sessions": [
    ... // Session objects from mongo
  ]
}
//Does not make a difference what data is returned, same error regardless.

// And this is the error returned

Error while loading route: TypeError: Cannot read property 'map' of undefined
    at Ember.EnumerableUtils.map (http://localhost:8002/vendor/ember/ember.js:1865:15)
    at Ember.Object.extend.pushMany (http://localhost:8002/vendor/ember-data/ember-data.min.js:10:2763)
    at c.extend.load (http://localhost:8002/vendor/ember-data/ember-data.min.js:9:16905)
    at http://localhost:8002/vendor/ember-data/ember-data.min.js:9:28425
    at invokeCallback (http://localhost:8002/vendor/ember/ember.js:9753:19)
    at publish (http://localhost:8002/vendor/ember/ember.js:9423:9)
    at Promise.publishFulfillment (http://localhost:8002/vendor/ember/ember.js:9843:7)
    at Object.DeferredActionQueues.flush (http://localhost:8002/vendor/ember/ember.js:5893:24)
    at Object.Backburner.end (http://localhost:8002/vendor/ember/ember.js:5984:27)
    at Object.Backburner.run (http://localhost:8002/vendor/ember/ember.js:6023:18) ember.js:3461
logToConsole ember.js:3461
defaultActionHandlers.error ember.js:34908
triggerEvent ember.js:34983
trigger ember.js:34116
Transition.trigger ember.js:33952
(anonymous function) ember.js:33809
invokeCallback ember.js:9753
publish ember.js:9423
publishRejection ember.js:9851
DeferredActionQueues.flush ember.js:5893
Backburner.end ember.js:5984
Backburner.run ember.js:6023
Ember.run ember.js:6426
c.success ember-data.min.js:8
fire jquery.js:1037
self.fireWith jquery.js:1148
done jquery.js:8074
callback jquery.js:8598
Transition #0: sessions: transition was aborted ember.js:3461