Network issues are not only about WiFi coverage, unfortunately, but as soon as you’ve determined what it isn’t, it will likely be that exact thing. 

Or, it might be external the wifi interference from ‘outside’ your network, since line in streams, such as from your TV, require more bandwidth than a normal music stream. 

I’d reopen your call with Sonos, and provide them more data, so they can help you track this down. 

Adding in here: when listening to TV audio when watching broadcast TV via antenna, there is no audio stuttering/choppiness.

Sonos can be very unhappy with “internet range extenders” and I don’t think they are even supported. A mesh system is very different thing, performs well with Sonos and is supported.

Can you tell us more about your “internet range extenders” so we understand your issue better?

Part of the “Apple only” problem may be the quality / bandwidth use of the music source, can you select the Ultra and add a UHD stream to it and then try grouping?

I recently unwired several Sonos to go fully WiFi and I see no difference in the connections although the WiFi troubleshooting info is more useful to me than the old web page chart.

Hey Stanley, thanks for the reply.

I have AT&T Fiber, so I have to use their hardware. The current equipment I have are:

Modem/Router - BGW320

WiFi Extenders - AirTies Extender Model 4971

I’m not sure if it makes a “mesh” network or is just extending it, but again, I never had an issue with the original Arc (bug again, not sure if SonosNet circumvented this). I have had these extenders the entire time I’ve had my Sonos system and the system works fine with everything else I throw at it.

Regarding your second question; I’m not sure I understand what you are saying when I should try to add a “UHD stream.” Do you mean using the Sonos app to play a Lossless or Atmos song on the Ultra first? Or something else? 

Different quality streams are labeled differently, UHD Ultra High Definition is the highest bitrate Stereo one.  For example Amazon Music Unlimited has:

HD (850 kbps),

Ultra HD (3730 kbps)

As you can see the UHD stream puts a lot more stress on your hardware and local network, the internet link too but that is rarely an issue today.

Extenders: https://support.sonos.com/en-us/article/sonos-system-requirements

I can’t find anything Sonos specific on your AirTies 4971 Wi-Fi Extenders.

Your router though can be switched into a passive / passthorugh mode that would let you use a different fully supported Mesh router.

https://help.sonic.com/hc/en-us/articles/1500000066642-BGW320#how_to_configure_your_bgw320_to_work_with_a_3rd_party_router.

With the extenders active I hesitate suggesting a diagnostic submission and call to Sonos Support, the hold times can be long and the chance of being told your setup is unsupported a bit high. Maybe power them down, reboot ALL Sonos and then see if you have issues, if you do then submit the diagnostic and call in, Sonos should support you in that situation. Plug the extenders back in after the call and testing Sonos stability without them powered up.

A not so clean option that can work is to add a Travel Router to your network, have Sonos and your Controller connect to it, that will hide the extenders from Sonos.

Thanks; I’m really hesitant to go with PassThrough mode as I’m very inexperienced with messing with network settings. 
 

Man this is frustrating; again, I never had this issue with extenders or grouping TV audio on the original Arc. 
 

It’s also so strange that TV audio grouping works fine when using other sources like broadcast TV (which I tested last night). 
 

One other thing I’m curious to try is hardwiring my Sonos Port into my network to create a new SonosNet between the Ones. I’m now doubtful that’ll solve it but figure it’s worth a try.