DIAGNOSIS The monitor is not waking from sleep properly with the PC. A power state handshake failure.
FIX Disable monitor deep sleep. In the OSD, go to System > Eco Solution. Set 'Standby Mode' to Off. Also, in Windows, go to Power & sleep settings > Additional power settings > Choose what power buttons do. Click 'Change settings that are currently unavailable.' Uncheck 'Turn on fast startup.' Restart.
IF THAT DIDN'T WORK The issue is often the DisplayPort cable. Replace it with a certified VESA DisplayPort 1.4 cable. Cheap cables cause handshake problems. Also, try a different DP port on your GPU.
HEADS UP Always turn on your PC before the monitor. The G7 can be finicky about detecting a signal if it's powered on first.