The Oppo firmware is up to date. The AVR, not so much. I reckon that would be the first place to start.

I use the Oppo players because they play well my Lumagen XS. I sent the XS the raw video output.

I did a quick search at AVS, despite my earlier declaration that I wouldn't. It's hard to interpret comments, but it would appear that there is a hardware issue with the older units and Atmos, bitstream. If the comments I skimmed through are correct, I either need to upgrade to a unit with the "5" designation, or send my AVR PCM.

I'll just give Oppo a call.