5.1 content isn’t decoding properly with devices that are connected to the HDMI 4 input. The content outputs correctly using the same devices with the other 3 HDMI inputs.

I connected a Roku 3 to the HDMI 4 input. The source indicators show 5.1, but the output indicators show only 2.1, and that’s what I’m getting. Status shows Dolby Digital Plus 3/2.1.

So I moved an Apple TV to HDMI 4. The 975 source and output indicators show 2.1 only. Status shows Multi PCM 3/2.1.

Cable box in HDMI 4: The 975 source indicators show 5.1 but the output indicators show (and I’m only getting) 2.1. Status shows Dolby Digital 3/2.1.

Thanks for any ideas to help diagnose.