I’d be checking the Hisense for firmware updates. Sonos plays what it is sent. The only reason for it to stop playing is it isn’t being sent data,

You might also want to check the HDMI cable between the two, and reseat it. 

I’ve checked the HDMI cable to make sure it was seated and tried a different HDMI cable as well. Unfortunately it did the same thing. What confuses me is that it very consistent at changing to the TV speakers at 10 minutes. It’s frustrating because it sounds amazing when it is playing through the Sonos system and the TV speakers are garbage. I also have the most recent firmware update. Tonight as I type it is doing something different all together. It is actually reconnecting for a few minutes and then disconecting again. Prior to this I had to reconnect it.

Then I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

In the past, there have been several complaints which seem to be around Hisense’s implementation of CEC and HDMI ARC, so Sonos may not be able to help you. One of the reasons I suggest checking for updates of the TV.

Do you have any other devices connected to the TV?

Airgetlam thanks for the advice on the system diagnostic. I ran one with Sonos yesterday, but I like the idea of right after the error. I ran one right after the error so I will forward that to the Sonos team. I spent a lot of time on the phone with Sonos and Hisense yesterday. Both teams were only concerned with the TV settings which unfortunately made no difference. I sent an additional message to Hisense last night as well. They both seem to be ok with just saying there is a compatability issue rather than contacting the other company to make an update that will correct the drivers. The misscommunication seems to be with the Hisense auto HDMI ARC. If the two companies would talk to one another I believe they could push an update that correct the problem on either side. Clearly Sonos works with other TVs and Hisense works with other sound bars so its got to be a programing issue.

GuitarSuperstar I have an Apple TV that is extender through a matrix and CAT6 extender to the TV. Although I don’t use it much I primary use the TVs apps.

If you disconnect everything but the Arc Ultra from the TV, do you still experience the problem?

GuitarSuperstar-I will have to give that a try. I’m not sure we did that when I was on the phone with Tech support.

GuitarSuperstar- You were right for some reason my matrix extender was causing issues even when I wasn’t viewing video from that device. Just being connected caused enough interfernce.