There are a ton of issues with Xbox One and NAT. Too many to list in a single post, but here are a few:
- Auto on on the Xbox One can interfere with NAT
- uPnP on your router can interfere with NAT
- You have to make sure you do a cold reset after other fixes
- Two Xbox Ones don't play well on the same network
- There are ports you need to forward that aren't in the official Microsoft list. I vaguely recall 3 that weren't listed
It took me 3 hours of Google searches and adjustments to get 2 Xbox Ones playing Destiny together in the same house. I never could get both to show an open NAT at the same time.
Interesting. I'll try turning off Auto-on. Probably in the settings somewhere.
uPnP. I can turn that off on my router as well. As far as I understand, it's not even needed if you forward the right ports or use DMZ mode.
Cold reset. I assume this is when you hold the power button for a long time to turn off and then back on. Good idea. I'll make sure to do this after each network change.
I don't know about two xbones on the same network, but since the 360 also shares some of the same required forwarded ports, I deleted the 360 ones so that they don't conflict with the xbones'. As far as I know, only one IP address can be port forwarded to at a time.
I'll also need to look for those other xbone ports you mention. Apparently, ghosts was requiring ports 3075 and then 3076 for some people. Didn't work for me though.