What type of signal is the Arc Ultra receiving?

Maybe generate a diagnostics report and speak to Sonos support?

Bruce, I’m seeing Dolby Atmos when playing Apple Music.

Nik, thought I’d start here before going the support route.  Thanks for the tip.

With the new App and firmware we users, and the forum moderators, are seeing posts like yours with issues we haven't seen before. A couple quick user level tests/tweaks usually rule out simple solutions and Support is the only way forward.

Recent posts on reddit show a desire to give us more internal access but it may be a while co ing.

Interesting. I don’t have an explanation for this, it indeed seems like a bug, or some odd network issue. As ​@nik9669a suggests, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. 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.

I figured it out…

I used to use a Playbase that was wired.  It’s now gone.  The Playbase AND the Sub were hard wired.  For some reason having the Sub wired and the Arc Ultra use wireless caused this issue.

Unplugging the ethernet from the sub fixed everything.  Thanks for all the input

Alan