Prevent further action executions

I've got a list of downloads in a blog-posts. Upon clicking on the link I'm incrementing a downloads downloadcount property. In order to prevent further executions I've got this Item-Controller download. For some reasons alreadyIncreased is always false even on consecutive executions of the actions. Why is that?

import Ember from 'ember';

export default Ember.ObjectController.extend({

  alreadyIncreased: false,

  actions: {
    incDownload: function() {

      if (this.get('alreadyIncreased') === false){
        this.set('alreadyIncreased', true)

        this.get('model').incrementProperty('downloadcount')
        this.get('model').save()
      }
    }
  }
})

This is the template:

  {{#each download in post.downloads itemController="base.download" }}
    <p>
      <a {{ action "incDownload"  }}>
        {{ download.name }}
      </a> - {{ download.downloadcount }} Hits
    </p>
  {{/each}}