If find this double notification rather interesting, I currently use a Pebble time with my Note4 and whenever I receive a notification on my phone, my pebble and pushbullet(software used to sync all your notifications)... Which ever of those 3 I choose to clear the said notification, the other 2 clears in about 1 or 2 seconds automatically.
So I can't really say if the Hub does it or not but there's surely a possibility for this to work.