MEGASH0N

It's likely blocking a server it uses for the downloads, check when you start the download for anything blocked outside your radius, if there is then add it to your allow list - you may need to do this a few times to get all the servers, shouldn't be an issue after that. If you provide the IDs for those servers as well then we can add them to the whitelist

Not seen any evidence to suggest they're doing this no, other games like the football games are using some relay servers but not on CoD as far as I am away. Other than the VPN thing they referenced which I think they only did due to connection I don't think they've done anything else. We'll keep an eye on it of course.

Added

Do keep in mind around launch time the game servers are at their most volatile, stick with it, once the population decreases you'll see a marked change I'm sure. Also experiment with forcing different servers in case they're under less load.

It would be yes, there is something we're working on, I don't know if it would go to the extent of being able to Geo-Filter though

Yes that will potentially be a possibility but not currently

Note taken - really hates factory resets! Are there any settings on the router that you've made specifically for either device? Did you have the issue before making the port forwarding rules for example?

Set the port forward 3074 for you and then 3075 for the other device and see if that resolves it. Are both devices added to the Geo-Filter?

I'm not even sure this is a Netduma thing. I've been using ExitLag for about a week, and honestly, the game has felt great. The past two days, it feels exactly as you describe. Seems like squishy and delayed input lag. Sometimes, it's like input is buffered and then executes all at once causing weird behavior. My R3 lands tomorrow, so I look forward to testing out these scenarios as well.
 

Not that I know of no but it has been requested before so I will pass on the interest but there is no guarantee that would happen. I do know especially for people that have bad routing that it can really help. Appreciate you letting us know once it arrives!

I will certainly notify you when I receive and set it up. I bought it this morning along with expedited shipping. Hopefully it will be here before the weekend.
The VPN, applied to the R3, makes sense from an "order of operations" perspective. I think we will be in the same boat with ExitLag, but I'll find out. Has there been any discussion with them, or GearUp, on adding some functionality to tie into paid for service from the R3? It looks like GearUp has partnered with a few router providers to do so. 
Maybe I'm making more of it than it is. All I know is that, since having the real-time route optimization, I feel like I'm gaming in near "real time".  Pun intended. 🙂
There surely has to be more under the hood than route optimization to make this much of a difference though.
Thanks for digging into to this with me!