Have a strange thing. I plug in RX 5500 XT 1080p monitor and TV with 4K resolution. TV pluged in with 2.1 HDMA-DPORT cable, monitor with HDMI-DVI. When I run a games in TV it randomly shutting off. I use a different ways - plug only TV, with 1080p, with 30Hz and HDMI cable, but always the same thing - it shutting of in random time with picture on a display that connection has off.
One more thing when I watching a movie with a difference resolution sometimes the resolution of TV can changes with refreshing of driver program(Adrenalin).