Delay PubSubHubbub alert

I recently implemented PubSubHubbub in one of my apps that subscribes to multiple Youtube channels to receive notifications.

Unfortunately, since I started using it, there has always been a fairly long delay between the video being loaded and the server receiving the notification.

From an analysis of the notifications I receive, it will be seen that I only get notifications when the video is "updated" but not "published", for example:

<published>2017-07-03T14:00:08+00:00</published>
<updated>2017-07-03T16:22:36.514463723+00:00</updated>

      

        
        
        
      

    

This is from the last video notification I received, my server got it almost exactly 2017-07-03 16:22:36 but the video was uploaded more than 2 hours ago (and was visible on their channel). Is this a hub issue or is it potentially missing something in my implementation?

Thank you in advance