Any off the top of your head suggestions? With the kludge in place, a proper fix is not worth much research time. It may have turned up just after an auto-patch a few days ago, I didn't pay attention.

This system is running an Nvidia GeForce GT 620 dual head setup with different monitors. The drivers are up to date according to the Nvidia software.

The problem:
After a regular display time-out the #1 display comes back on but the #2 stays dark. If I cycle the monitor's power button it will wake up for a couple of seconds and then go dark.

I've figured out work-arounds that I will share below. BUT they are stupid manual kludges.

First though, some more behavior:

Switching between users during the symptom:
From a regular user to another one - same problem
From a regular user after the kludge fix - same problem
From a regular user to an admin - proper behavior, no problem
From an admin to a regular user - same old problem.

4 different kludge fixes:
Cycle the monitor off - on, in the two seconds available press the monitor's menu button - the monitor stays on after the menu closes <--<<< BEST
Adjust something trivial in the Nvidia control software, enough for the [Apply] button to appear, then...
-- slide the Nvidia software so the [apply] button is in the dark screen
-- move the pointer blindly over the [apply] button
-- Cycle the monitor off - on
-- get the button pushing timing right
-- click [Apply] before the monitor goes dark, success <---<<< Who needs video games with challenges like this!?!
In power settings adjust monitor to Always On, fix it with kludge and get on with the day.
And of course #4: Reboot!

I've had these monitors working together through many different hardware cycles over the years, and this is the first time they've acted like this. The uncooperative monitor doesn't appear to have any hardware menu settings that relate to the problem.