I've got a new AMD RX580 Nitro+, running on a Ryzen 5 rig. Also, a new Samsung C27FG 144hz monitor. After 5 minutes in certain games (e.g. Divinity 2, XCom 2), many of the colors on the screen turn bright blue (not the whole screen). This problem persists if I quit the game and go to desktop. This occasionally happens in Youtube videos as well, but not with other video apps or with MS Word, etc.
There are also thin lines flickering at the very top of the screen, only in dark colors, only at 144hz.
Ratcheting down to 120hz usually returns the regular colors, as does turning the monitor off and on again (sometimes).
New Dp 1.2 cable (certified)
Updated Radeon drivers
I also RMA'd the monitor to Samsung, but they found no fault.
Thanks for the help!