This is happening to me as well. M1 Mac Mini and trying to update to 11.4

Similar issue here. Mac mini (M1, 2020) Two external monitors (ASUS PB278) MacOS 11.0.1 The monitor hooked up via HDMI to HDMI works fine, the monitor hooked up via USB-C to HDMI doesn't work. The monitor that doesn't work IS recognized by the OS, I see it in displays but only black on screen. I've experimented with unplugging/rebooting/pram/etc. and I've seen both monitors work for a few seconds then USB-C to HDMI monitor goes back to black...