Sounds related, bit not quite the same..:

My Arc switches back to the source it was on before selecting TV input, though (luckily) it does not start playing.

The Playbar I had (on trial) before getting the Arc, did not do that, but maybe that is the S1 way..

it is, though, very frustrating to have the source change when I have not enabled the Auto-change to TV source option...

@Richc72 I am having a similar issue with the new Arc Soundbar but only when I turn off my Sony XBR-55X900H using Alexa. When I use the remote to turn off the TV, I get a quick flash of the green mute light, but then goes off. I’ve been round circles with support and done several test for them but the are stumped. Please let me know if you come up with a fix and I’ll do the same. 

@marook not sure if its exactly the same situation as yours, but I’ve seen a few threads that sound similar. Check this one out. It might help. Good luck.

https://en.community.sonos.com/home-theater-228993/arc-with-sony-bravia-oled-tv-system-turned-off-in-mute-status-6843027?postid=16441819#post16441819

Hi everyone, sorry for the late response, thank you for reaching out and @Richc72 welcome to the community.

@Richc72, I would like to know how you turn off your TV that mutes the Sonos Beam.

@marook, can you explain further on how you use the Sonos Arc. 

@William_61, if you remove Alexa and manually turn off the TV with the remote, does it mute the Sonos Arc?

To explain why the Playbar doesn’t do this is because it uses an Optical connection. Optical connections only have the audio from the TV going one way to the Playbar.

While the Sonos Arc and Sonos Beam have two-way communication with the TV through HDMI-ARC connection with the HDMI-CEC function.

The more information you can provide is greatly appreciated.

@Kyle A Thanks for your interest in my issue. I did your scenario and here is the diagnostic: 155 555 3236

When I remove Alexa and manually turn off the TV with the remote, it does not mute the Arc. This is the same response I get when using the remote with Alexa enabled. No matter how I slice it, the only time the Arc gets muted is when I turn off the TV using Alexa. 

Also, I have a case number open. I did run a few tests for Frank E. It is Case #: 019*****

He had me turn TV on/off with remote 5x which ran normal, no muting. Diagnostic: 128 478 8928

He also had me turn TV on/off using Alex 5X which muted the Arc each time. Diagnostic: 977 666 3554

Interestingly, when I turn off the TV using Alexa and she mutes the Arc, giving me the green light, when I ask Alexa to play music in that muted state, the music plays. I find that odd since it was showing as muted.

A fresh pair of eyes on the issue is appreciated. Thank you and please let me know if you have any questions.

**Moderator Note: Please censor personal information when posting.**

Hi @William_61, thank you for the update.

I checked the diagnostics and yes, I do see it getting muted whenever Alexa is being used.

I would like you to test the beam with Alexa if we see the same behavior.

When asking Alexa to play music and you see the player becomes unmuted, that’s normal behavior.

However, using the Sonos app to play in the muted state will not unmute the player.

Update us with your findings and feel free to reach out with your other concerns.

@Kyle A 

hi, I turn the tv off both through google assistant and the remote. Same problem either way.

@Kyle A I was able to test my Beam in place of the Arc on my new Sony XBR-55X900H. It also muted the Beam and showed the green mute light when using Alexa to turn off that TV. So it seems to be the Sony X900H which is the culprit. 

FYI, the Beam, which is normally connected to a Sony XBR-43X800G in another room, does no exhibit the muting behavior when using Alexa to turn off that TV with it. 

Maybe with future Sony updates the issue will resolve itself. We will see. Thanks for help and ideas!

Hi @William_61 and @Richc72, thank you for the update.

@Richc72, I would like you to disconnect the beam from the XBR55x850D and turn the XBR-55X850D off with the remote.

We’re just going to check if the remote also mutes the beam. 

For voice services, unfortunately, in order for it to turn off the TV, the beam needs to be connected to the TV.

@William_61, could check the Arc connected to the XBR-43X800G and see it gets muted.

If not, we have isolated that the XBR-55X900H is muting the Home Theater speakers.

Update us with your findings.

@Kyle A Sorry for the delay. Was able to finally test the Arc on the XBR-43X800G and it did not mute the Arc when using Alexa to turn off the TV. So we have isolated the mute culprit to being the X900H but only when commanded via Alexa. Maybe in some future X900H update, that mute signal for third party command will be fixed. Thanks for all your efforts. Btw, we love, love, love the Arc. Its been a great addition to our Sonos family! 

Hi @William_61, thank you for the update.

No worries, I’m glad you’re enjoying the Sonos Arc and we have isolated the issue.

If you have other concerns, feel free to reach out.

Hi @Kyle A 

Thought you’d be interested in the fact my issue has been resolved! I am on the Beta team for Sonos Software updates and after the most recent update, the green mute status light on the Arc and Surrounds no longer stays on when turning off the TV using using Alexa. 

Weird huh. Have a good weekend!

@William_61 When do you think the rest of us non-beta mortals get the update?

I’m a little concerned about joining Beta and having something that’s working get messed up.

@MSterling I have no idea when beta versions go live. Just a tester. Sorry.

Seeing same issue with Sony xbr-65X850f. It began after the November update to Android. Happens when I turn the TV off with the power button on the remote - all the Sonos have a green light on them. I believe it’s because the TV doesn't send a “power off” signal over HDMI-CEC. When I use the Apple TV and turn it off, it sends a signal to all HDMI-CEC devices and the Sonos turns off (doesn’t go to mute).

This soundbar is annoying. It's always muted when turning on the tv. Even when playing a YouTube video after a few minutes of audio silence the bar takes a few seconds to wake up. The TV is a QN65Q60TAFXZC, connected with eARC.

I'll never buy a soundbar again. My $300 vintage stereo and loudspeakers I got off Kijiji sound much better.

@EvilKittenLord Is Anynet+ set up on your TV? Is TV Autoplay enabled in the Sonos app?

Yes, @GuitarSuperstar. Anynet+ (HDMI-CEC), TV Autoplay, and Ungroup on Autoplay are all enabled. I don't have other rooms, though, so am disabling UoA.

I’m late to this thread, which I just found after researching the mute problem with my Beam when turning off my new TCL TV. Previously the bean was hooked up to an older Samsung, which didn’t cause this problem.