Yeah I found that same map with the mystery zone through google and tried all means to trigger it but no luck. From what I've heard there hasn't been any actual proof that you can get 21/21 regions at the moment. I've been fault finding and looking for solutions for the past three days. I've spent 140 hours in-game and at least 25 of those hours has been looking for solutions to the bugs that prevent completion of the collection and some quests. heck still can't find a couple of mosaics in the Hinterlands and other areas.
I have 20/21 as well and it has been driving me nuts, lol. I have 21/21 in Emerald graves, and that was a pain in the buttox as well. There was one really tiny region that is very easy to miss, which I thought might be what was happening with the plains too, but I had no luck with that. I am also missing one region in Emprise Du Lion.
i cant find the 21st region as well.
It's a pain but in the south end of hte elven graveyard there is a una'din grotto. I wasn't going grave robbing on my play through so missed it till I was region hunting. You have to run right up to the door to trigger the region, but you don't have to do the grave robbing quest.
