Ubuntu MATE 21.04 doesn’t turn off external monitor

I am using lenovo ThinkPad W540 which has an nvidia gl107glm and Intel video cards but I cannot tell which on is used for display port. Using the mate 21.04 with the laptop lid closed and external monitor connected to the display port and internal display turned off and external display set as primary, screen will go into power saving mode. The issue existed in mate 20.10 but when booted into kde neon 20.04 it works as expected. Any help would be appreciated.
-scott

I tried using "xset dpms force off" which does turn off screen briefly then within 30 seconds the screen turns back on.

I installed regular ubuntu 21.04 and had to change the display server from wayland to xorg for the screen power saving mode to work properly. Is Mate using xorg or wayland by default?

MATE doesn't support Wayland at the moment.
There's work going on for supporting it, but it's far from being ready.

So that nixes that path. Does anyone have any recommendations on how to troubleshoot this? I found one thread that seems to match my issue back in 2017 but there was not resolution to that one either but same issue.

Are others out there experiencing issues with there laptop connected to external monitor not putting the monitor in sleep? Is there not a supported hardware standard for a monitor that is 3 years old?

Is this something unique to mate or is it relying upon power management from core services?

Did a new install of 21.10 and have the same results as far as external monitor not going to sleep after timeout period reached. I installed kde neon and that does work so I am at a loss as to what to do and further trouble shoot. Any help would be great.

thanks

I added the nvidia 390 driver to my kde neon partition and was able to break the working behavior. Uninstall the driver was able to restore the working behavior so the issue may be around the nvidia driver. I had thru xset command was able to trigger a screen sleep and thought I fixed it but that was a fail. Still need to figure our the command and if I am able to duplicate the sleep.