There's a similar post here with 'don't use a UPS' as an accepted solution - well, I don't have one and this still happens.
Some details: U32H85x 4k monitor, latest firmware.
Steps to reproduce: have something plugged into the DisplayPort. It does not need to be the selected source. The DisplayPort cable does not even need to be plugged into a computer on the other end.
What happens: as soon as the computer goes to sleep (it can be connected via HDMI or said DP), the monitor will go to sleep, then wake up after 2-3s, go to sleep again, wake up and so on until the backlight dies, I guess...
The only workaround I've found so far is to have nothing plugged into the DP connector on the display. Have not tried the mini-DP port.
