I have had video dropout problems off and on since before I had this projector. I've been letting my 500es perform the upscaling while I have switched out my AVR to the Denon X7200W and noticed no problems. I have watched about 45 mnutes of movie material on my FMP x10 in UHD without dropouts.
The other day I decided to try out madvr and a direct scaling to 4k from PC. I got an hour into a movie and got the dropouts again for the first time since I replaced my AVR. This was on Input 1. I had a hard time getting it to accept a picture again, but finally did on Input 2, where despite some dropouts shortly after connection I then got no dropouts for the remainder of the film, though I scaled back & let EVR do the scaling & DXVA do the decoding. I went back to 1080P and the projector doing the scaling and no more dropouts at all, even on Input 1.
I know there's been at least one firmware update. Does it address any HDMI handshake issues? I haven't updated partially because I believe in "if it's not broke, don't fix it" and partially because I have no ethernet cable near the projector. I'm willing to use a long run & update the firmware if it might help. I know with my previous AVR which was an Onkyo things got easier on the dropout front once I installed updated firmware.