I had a system that was having trouble executing commands. I have a few instruments that you don’t have and I could see that there was quite a lot of IR trash being received. By accident I noticed that when I stood in a certain spot the trash was gone. It turned out that when the sun was shining on a certain section of wallpaper, the wallpaper emitted IR and my body was casting a shadow on the IR receiver.Mostly, the IR trash simply slowed response because the trash was interpreted as invalid commands by the devices, but occasionally there would be an incorrect response because the command was modified by the trash.
With respect to ROKU commands switching inputs on the receiver, this is probably caused by CEC and your old DENON probably did not support CEC. A CEC blocker inserted into the ROKU HDMI cable might resolve your issue.
