Ember.js Error when updating properties

error

Uncaught Error: Assertion Failed: An attribute binding was triggered when the element was not in the DOM
  ember.js?body=1:3903
  Ember.assertember.js?body=1:7393
  applyAttributeBindingsember.js?body=1:41697
  merge.invokeObserverember.js?body=1:43838
  CoreView.extend._wrapAsScheduled.stateCheckedFnember.js?body=1:849
  Queue.invokeember.js?body=1:914
  Queue.flushember.js?body=1:719
  DeferredActionQueues.flushember.js?body=1:144
  Backburner.endember.js?body=1:547
  (anonymous function)

markup-that-changes.handlebars

<li id="activity_start_datetime_input">
  <label class=" label" for="activity_start_datetime">Start</label>
  <input class="datetime" id="activity_start_datetime" name="start_datetime" type="text" {{bind-attr value="schedule-item.start_datetime"}} />
</li>
<li id="activity_end_datetime_input">
  <label class=" label" for="activity_end_datetime">End</label>
  <input class="datetime" id="activity_end_datetime" name="end_datetime" type="text" {{bind-attr value="schedule-item.end_datetime"}} />
</li>

snippet-around-executed-code.js

return _this.getAttendeeData(idents).then(function(data) {
  schedule_item.invitations = _this.processInvitations(schedule_item.invitees, data.attendee_list);
  return _this.get('model').setProperties(schedule_item);
});

Thank you sean <3