Using the same selected output from the OPPO for both HDMI1 and HDMI2:
Never use cable or broadcast for movies; always shiny discs (DVD) and Blu-Ray when available.
Examples recently were "Generation Kill" and the "Titanic" 4 series version made for TV (60Hz).
The HDMI1 is routed directly to the projector and the HDMI2 output is routed through the ONKYO 805 amplifier. The latter video output from HDMI2, never
shows this problem (HDMI2).
Whatever the 'special processing' out of HDMI1, it always looks better than HDMI2 except for this problem on 60Hz material and only intermittently.
It is hard to ignore the 'effect' on faces.
Definitely a problem.
I don't think we see this with Denon 2500. I will double check and report specifc encounters next time it happens.