Diagnosis
A handshake failure between the PC's graphics card and the monitor during the sleep/wake cycle. This is often a driver issue or a power saving setting on the monitor.
How to Fix It
First, update your graphics card drivers to the latest version from NVIDIA or AMD. Perform a clean installation. Then, disable the monitor's deep sleep function. Use the rear joystick to open the OSD. Navigate to Settings -> Power Button. Set Power Saving to Off. Also, set Zero Delay to On.
If That Didn't Work
Adjust Windows power settings. In Windows Control Panel > Power Options > Edit Plan Settings > Change Advanced Power Settings. Expand "PCI Express" > "Link State Power Management" and set it to "Off." Also, in the same menu, under "USB settings," disable "USB selective suspend setting."
Heads Up
This issue is prevalent with NVIDIA GPUs when connected via HDMI. If using HDMI, switch to a DisplayPort cable as the primary fix. The monitor's power LED will glow amber in sleep mode. If it is completely off, the deep sleep function is active and causing the wake failure.