Since upgrading to macOS High Sierra 10.13, I've been having an issue with my late 2016 15" MacBook Pro (Radeon Pro 455 graphic card). The problem is still there on High Sierra 10.13.1 Beta 1. I'm using it connected to an Asus MX27UC 4K USB-C display. After waking up the MBP from sleep, the external screen picture will not stay on. It will lose sync every 10 seconds or so, only to work again a couple of seconds later. It will basically flash on-off in a 10-2 second rhythm. Subsequent sleeps and resumes, as well as unplugging and re-plugging the display to USB-C will not help. A reboot also won't help. The only fix is to shut down the MBP and start it up again. Then it will work - until the next sleep. This can also be reproduced by unplugging and re-plugging the display to USB-C while the Mac is running. It seems that it will only sync properly on the first time after booting. On subsequent syncs it will fail. Disabling "automatic graphics switching" to leave the Radeon 455 always on doesn't help either. It only happens when using the display in its native DisplayPort over USB-C mode. If I connect it through a USB-C to HDMI adapter it works properly. It seems like they screwed up the Radeon display drivers with High Sierra. Is anyone experiencing similar issues with external displays?