The only way I’m aware of to ‘reset’ that is to actually unplug the PLAYBAR from power for two minutes, then plug it back in while the PLAYBAR is in the intended orientation. I don’t believe there is any software method to do this. 

Thanks Bruce. That's actually what I'm trying to do now, just not a whole lot of luck. 

Also realized that my Playbar has been mounted "upside-down" according to the installation guide for years (silver bar should be at the bottom), so seeing if that helps. 

I don’t know if there’s capacitor in that circuit path, but it might be worth leaving unplugged for longer than two minutes, in order to de-energize it. It’s also feasible that it’s broken completely, although that would be a super low possibility. And I don’t think there would be any data about it in a diagnostic.

I don’t even know if they use a liquid filled switch, or some other device, so it’s hard to troubleshoot. It’s a pretty rare issue, so I wouldn’t even be confident it would be covered in the scripts/knowledge base of the phone reps. But calling in and creating a ticket might get it booted to a higher level of support, rather than some random internet troll like me. 

There is a way to get the orientation of the device at the UPnP level, but there is no way to set the orientation.