DisplayPort acts as plug&play (pnp) devices, so when display is powered off, the device will disappear. This will cause issues in multi-monitor and MST (DP Daisy-Chain) configurations.

Due to the device disappearing and reappearing, the display ID will change and settings like rotations and positions will not point to the correct display any longer.

Options:

• Disable DCC/CI in the monitor settings. This will disable bidirectional communication between the monitor and the pc.
• Enabling DisplayPort 1.2 settings in monitor may help (required for MST anyway)
• Disabling screensaver/power saving options to switch off the monitor can act as a workaround

These linux commands to turn monitors off and on in case they do not come back from sleep:

env DISPLAY=:0 xset dpms force off
env DISPLAY=:0 xset dpms force on