So, I know there are lots of posts about this issue, so apologies for piling on, but I haven't seen any that answer this case...
I have a Roku 3, which I've had since about 2013. My setup (Denon AVR, LG TV and Roku 3 with Plex) has been unchanged since about 2016 and I've never had and problems with PSoD... Until about 3 months ago. Since then, every time I turn off my TV or Receiver or switch AVR Inputs, while Roku is powered on, it will get ( 100% of the time ) the HDCP error on next playback.
Rebooting the Roku when the TV and AVR are powered on and set to the correct channel it works 100%, no errors, but that means I am rebooting the Roku several times a day which is pretty frustrating.
I've tried all of the troubleshooting steps, changing cables, ports, factory reset, firmware updates on the TV, AVR, and Roku.
Roku support were no help, they blame the AVR, even though no other devices (DVD Player, set to box etc) have similar issues in the same setup.