Discovery
From ThresholdRPG Wiki
As you wander the realm, you will discover areas or zones just by walking into them. These are called territories. You may notice that places you have been before, often quite a lot, will reward you with a notification that that you have discovered a new place. This means that you did not have this as a territory on your list of discovered territories. This is not unusual. It is not a bug, unless, you already had it on your list of known territories and you are getting the notification a second time.