I found a locked golden chest but can't find the key. Where is it?

I explored the large area called the Temple Steppes and found a locked golden chest. I'm guessing there is a large champion I need to kill in order to get the key but I can't seem to find it. I've looked all over the map and had no luck. Is this a bug? Is the key somewhere else? Did I really just miss the champion?

Find an enemy called Bittersprite on the same map as the Locked Golden Chest. Bittersprite looks like a large wasp or hornet. It is not necessarily near the chest, it can be anywhere on the map. You can see it floating in the top-right area of this screenshot:

Kill the Bittersprite and it will drop a Golden Key. The key will not appear in your inventory when you pick it up, but in the top-right corner of the screen it will say -You Found- and show a picture of the key. You can now open the Locked Golden Chest.

You have to kill a mob called Bitter Spire, it's a bird

It's located to the right of the waypoint.

Take 2 right turns from the waypoint, basically head west. It's no more than a 4 second run from the way point. You may have to clear the map first, like I did.