Controller computed property based on model only valid in loop

I have a the following in Ember

Route

model: function() {
  return this.store.findAll('competency');
}

Controller

calendarItems: Ember.computed('model', function() {
  return this.get('model').map(function(competency) {
    return {
      'name': competency.get('title'),
      'start': competency.get('endDate')
    };
  });
})

Template

{{#each model as |item|}}
  {{log calendarItems}}
{{/each}}

{{log calendarItems}}

For some reason unknown to me the {{log calendarItems}} inside the loop displays correctly with all of the store items in the models mapped correctly. But only when the {{log calendarItems}} is not present outside the loop.

When the {{log calendarItems}} is also present outside the loop it causes all 4 log statements to return [] as though the model had nothing to map.

If {{log calendarItems}} is on its own it also returns [].

Am I missing something fundamental about Ember here?

Thanks in advance, Ryan