Anyone else use Coax? Cannot watch any DVR and Some channels on Coax output after Firmware upgrade

Update November 11, 2020 - Does Xfinity read these? 

This situation continues to get worse.  New discovery - tried watching 1115 NEWSMAXTV - THIS is NOT a DVR, THIS IS A LIVE CHANNEL - and Destroys coax output immediately.  Tried in normal 4K 2160 which of course fails, requiring changing to known good channel and restarting - AND setting Receiver to 480 SD mode, lowest resolution, attempting to load 1115 STILL fails.  Apparently this channel is only sourced in UHD or higher.

DVR issue continues - Attempting to view anything on DVR still cancels Coax out signal requiring Restart to restore coax to work again.  These are Xfinity DVR recordings.  Peacock and other 3rd party movies work.  Some very old movies if they were only available in SD will play, but most fail.

The clincher -  WHY I NEED HELP - is this failure mode requires a Restart.  Try watching an on-demand movie, tried 6, each required a restart, and some restarts get queued as 15-20 minute Refreshes instead of the 3-4 minute restart.

ALL of my DVR recordings played fine BEFORE the firmware update to the receiver.

I offered a solution: Add another menu item to Device Settings - Video Settings so the result looks like this:

  Video Output Resolution (HDMI):  16:9, 2160p60 4K UHD (Best Available) 

  Video Output Resolution (Coax): 4:3, 480p SD

This change would allow the user to select what resolution they want for each output.

Considering IT IS POSSIBLE to change the output of each (I know coax worked prior to firmware update around 9/1/2020 with my display set for 2160p, outputting 720p over coax to my TV - Comparing screen resolution seen between 480p and 720p - I know it was showing at 720p over coax before).

I write software, it is possible - just seems Xfinity doesn't care.

Can someone please respond: Xfinity???   Does anyone else use the coax output?   Do you have the same issue?

UPDATE Sept 13, 2020 - More than a month with this problem, and a week without any contact from Xfinity regarding this problem.  The 9/3 Xfninity technician confirming the problem is known after he spoke with his manager.  I though support could help resolive this, but it looks like I will have to take what he said literally: He told me 'call billing and have them adjust your bill as this will likely not be fixed'... 

A call to support a week after Xfinity replaced my receiver; the customer service represantitve 'confirmed this has been escalated and promised a call from 'Advanced support' - yea,  still waiting... nothing...

Problem: Attempting to watch an OnDemand movie or DVR recording will destroy the coax out TV signal, and lock it's output in some mode preventing it from working again until the box is restarted.  The remote TV will report 'No Source' or 'No Signal'... 

My configuration has not changed in 3+ years beyond replacing a 1080p HD TV with a new 4K TV last Christmas, so I've had a new 4K X1 Receiver since (I think it's an ARRIS XG1v4)... 

The new problem is the output to my long existing 2 remote TVs on coax out disappears if any On Demand or DVR recording is played resulting in NOT being able to watch on my existing TVs:

• an old 15" Emerson in my office, something to watch/listen to while working (I have tinnitus so a 'quiet' office literally is bad, must have something on in the background to concentrate).
• a 50" Sony Bravia HD capable TV in the bedroom, not HD capable via coax.  Only via HDMI and I do not have an HDMI cable that would reach across the entire house, and can't anyways with only one HDMI output... and it's fine in SD...  

I only desire to watch the exact same thing either in 2160p 4K in my living room where the receiver is - or - in normal output via coax in the bedroom or office.

For 3+ years I have enjoyed watching On Demand and DVR shows on both 4K and low resolution remotely...  
I cannot enjoy movies remotely anymore!

I had an Xfinity service guy out last week.  He replaced my receiver, and the replacement had the same problem.  He talked with his supervisor for quite a while (in private outside surprisingly), then returned and suggested I try changing the main display resolution to 720p.  We did this and the office and bedroom worked.  Apparently they know about this, but don't want to change it. The tech suggested they want everyone to upgrade to using remote boxes to watch HD TV - why, I only watch 1 TV at a time with the same content on it.
One web-page states: "Coaxial cables can offer 1080i or 720p but not the 1080p HDMI can deliver."  I would bet most people who are using coax have older televisions and do not want to upgrade just to get interlaced 1080i TV.  

Simply - watching remotely via coax TV WORKS fine in normal TV mode - On Demand or DVR crashes the coax output completely and permanently (until a forced restart).

My guess: The moment OnDemand or DVR is activated, that with the firmware update 117+ (currently 119.0.0) Xfinity is setting the coax mode to 1080i  - and since this resolution is not supported on an older tv channel 3 - this causes No Signal messages since the TV cannot process a frame with that many lines...

THIS DOES NOT HAPPEN WITH REGULAR BROADCAST TV.

WATCHING ANYTHING IN ON DEMAND OR DVR WHEN RECEIVER IS IN 2160p DESTROYS THE COAX OUTPUT AND IS NOT RECOVERABLE:

• A FULL RESTART IS REQUIRED TO BE ABLE TO WATCH REMOTELY VIA COAX AGAIN
• IT IS NOT FIXABLE, EVEN WITH THE "exit, exit, exit 720" found on another forum related message, which does put the receiver in 720p display mode
  the output remains locked making use of REMOTE TVs IMPOSSIBLE.
• The problem is - if anyone watches an On Demand or DVR recording - and the average household member DOES NOT KNOW how to restart the receiver,
  the coax output is DEAD.  They cannot watch TV as they normally could.

I am now being denied TV Service on my remote TVs due to this firmware update.  

This is NOT Acceptable when it worked before, without any changes by customer - clearly changed by Xfinity!  

The below article link suggests a way to change the reciever to 720p mode pressing the 'exit, exit, exit, 720' button sequence - does NOT work for this receiver...

This is a long post, some of which sound like the same issue I am having   https://forums.xfinity.com/t5/X1/Intermittent-Video-Issues-Affecting-Some-Customers/m-p/3356842/highlight/true

Their solution was to press 'exit, exit, exit, 720' - and as one person responded, this only tunes to channel 720.

Changing my reciever to 720p and I can watch remotely without problem, then suggesting I  change back to 2160p60 4k UHD for the living room is insane.  I obtained this receiver to watch 4K, and now am told to change to 720p to watch coax output TV...
I work in my office M-F from 8 to 5, so you say I change should change it every morning at 8am to 720p so I can enjoy my tv in the background while working, then at 5pm change to 2160p 4K for watching until bed time, then back to 720p to catch a DVR recording at 10 pm if I want to watch something...

But - if an on demand or dvr recording was played at any time when it was set to 2160p - then YOU CANNOT WATCH ANYTHING without restarting the receiver.

Keep in mind - I did NOT have this problem before a recent firmware update! 

And to even suggest this is a solution (as the support technician was told to tell me) is literally insane!

I am not getting the service I am paying for right now.