Breach won't close

My breach would not close and give me the shards.

The mob counter on the map says 0 mobs remaining.
I do have the breach remains open tablet on the map however, I have searched the entire area and there is no more mobs in this map at all left to kill. I have spent at least 10minutes after completing this running around.

An indicator on remaining breach mobs on mini map may be nice in this situation as this is such a waste of time