Having read about a few similar issues in the 3.52-3.56 versions, I have found no recent reports that has a problem. I have two Philips 4k monitors, and none of them turn off properly, they keep the backlight lit trough the night.
Currently running opensuse with driver version 367.35.
What can I do to fix the problem? Turning the monitors off every night has it’s own issues with the screens not being detected properly when turned back on.