I decided to create this post since sandipt had suggested to investigate each separate case apart.
Several months ago I bought new monitor and connected it via DisplayPort to the GeForce 1050ti card.
Since that time I had an issue with the DPMS - standby|off|suspend mode does not work.
xset dpms force off - the monitor turns off for one second and then backlight turns on.
In case when the monitor connected via hdmi everything works perfectly.
Monitor: Dell p2317h
Card: GeForce 1050 Ti
Current driver: 381.22
Desktop Environment: xfce4, Mate.
nvidia-bug-report.log.gz (108 KB)