Monitor only Wakes up if PC power button is held down

Hello,

We've recently come across a problem where once a monitor goes to sleep it won't wake up unless you hold down the PC's power button for 4/5 seconds, when the monitor is on this same action initiates the shutdown procedure on the PC.

It's not specific to one brand of monitor and it's not all devices.

I have tried reinstalling Windows, the video drivers, I have tried different monitors, I can't see any settings that are causing this behavior.

The PC is not going into hibernation. I can access the PC via our remote software just fine but the monitor will remain blank (it's not a blank screen option on the remote software causing it)

Any help would be appreciated.