Remote pairing issue (RF specifically)

Hoping someone can help me here....

I changed out my Xfinity set top box (STB) yesterday due to a completely unrelated problem from what I am currently experiencing. The STB is the XG2v2-P model if that means anything.

So I installed the new STB yesterday and everything seemed to go fine with the setup. Picture comes up, my channels are loaded, everything looks great. So I move on to pairing the new XR15 remote with the new STB. And for whatever reason, the remove will not pair with the box.

I am able to pair the remote with my Samsung TV and my Yamaga stereo receiver just fine. Those are IR pairings though. And the remote does work fine with the STB when it is has direct line-of-sight and is sending IR signals (red LED on the remote). However when I try to pair it with the STB for that I can use voice commands and I can use the remote without direct line-of-sight via the RF signals (green LED on the remote) it will not pair at all. 

I am vitually 100% sure I am doing the process right. I go into the settings menu, then the Remote Settings, then choose the pairing voice remote option and follow the prompts for the X%15 remote of holding down the Xfinity button and the "i" info button. I do get the red LED at first like I am supposed to, and after a few seconds I get the blinking green LED like I am supposed to...... but at no point do I get a generated number code on the TV like it says I should. The green LED just blinks and blinks until eventually timing out. I did confirm the voice commands option is set to "on"

I did all of the basic stuff... reset the STB several times, reset the remote via the "A" and "D" buttons and then entering then 981 code. Still, the same issue. Also, I did have an old XR5 remote laying around. I reset this remote and tried pairing it as well. Again, it pairs to the Samsung TV and Yamaha stereo receiver fine, and it will work with line-of-sight IR with the set top box, but it will not pair for the RF portion. I spent an hour on the phone with Xfinity support last night as well, they did all the basic stuff on their end as well as far as resets and what not. I will say though, I don't feel their support reps understand the difference between the IR and the RF and therefore weren't really grapsing the problem, but that's a different topic for a different day haha. Based on where my STB is installed I absolutely NEED the RF to working because pointing the remote directly at the STB for the IR line-of-sight is not really the most convenient thing.

For the record, my old STB of the same model that I switched out yesterday was switched out for a completely different issue. The XR15 remote worked fine with both IR and RF on the old STB. When I changed out the STB at the Xfinity store they did take that remote and give me a new one, but being that BOTH the new XR15 remote and the old XR5 remote that I have laying around the house are having this issue, I really don't think it's related to the remote. Right now, my assumption is there is a bad RF transponder in the STB and unfortunately I need to change the box out AGAIN..... but I'm hoping someone might have a suggestion that I've overlooked?