Yeah I too tested multiple Optoma P2s against my Yamaha RX V6A and both had the same problem and was not until I got the Marantz SR5014 without the HDMI 2.1 that everything worked fine. The other problem I had with the first P2 was that it had to be physically placed 3 inches right of center to make the image centered on the screen, whether it got dropped in shipping who knows.Thank you! I just got the third Optoma P2 and tested it, works great!
And for everybody who hopes not every Optoma P2 is affected: now I tested three (!) Optoma P2 with my Denon X4700H.. ALL have the same problem.