EDIT: False alarm. I got into a game after doing the steps below. Closed down the game to report to forums. Once I started back up my NAT was unknown again.

Sorry to get your hopes up.

This worked for me. Hope it helps you all!

My full repro just in case it's a combination of steps:

1. Reboot PC
2. Cycle all routers and modems
3. Verify game files
4. Start game to verify NAT
5. Close game
6. Disable UPNP
7. Profit