OMG.. see if this helps you get the last one! I am going now to check it out also!
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'm still short one 1 region in the Plains, 1 seed, and 2 mosaic pieces for The Fall. I've got everything else. Oh, and I'm missing 8 banner varriations. It'd be a bit easer to track if they had the names of what you collected listed under the Collections section instead of having to dig into the Codex or remember where you've been,.
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.
