Yes, I don't get HDCP errors with FRM off. (According to the folks in the Roku section of AVS Forum, FRM is a well-known cause of HDCP errors with the Roku.)
Today I plugged the Roku directly into the TV instead of going through the Denon AVR. I had FRM on. Watched a Dolby Vision program for several minutes and got no HDCP errors. I had the TV sound going back into the AVR via the eARC port. Apparently there's some interaction with the Roku going through the AVR that's causing the HDCP errors with FRM on. So it appears that if I want FRM on my Roku (4802), I need to plug it directly into the TV instead of the AVR. I can live with that.
