GONK-
I think your remark about the 950 quirk is correct having empirically tested this notion by accidentally switching back and forth with the original source in different conditions, stereo and surround. This confirms my getting stronger-every=day notion of a software glitch existing from day one.

What had led me astray was not having any difficulty with the Sony NS999ES CD/DVD player the OPPO replaces.

Yes, the bypass is stereo input only; this is how I input my Rega P5/Ortofon/Grado phono preamp (most of my music is via my 3500 LPs rather than the much fewer CDs on hand).

I do thank you for your thoughts, maybe I can move up to the 997 when it’s available.