Diagnosis
This is a common issue with VA panels like this one when VRR is active at low frame rates, due to rapid gamma shifts.
How to Fix It
Cap your in-game frame rate just below the monitor's max refresh rate (e.g., 140 fps). Use a tool like RivaTuner Statistics Server. This keeps the frame rate high and stable, minimizing the large jumps that cause flicker.
If That Didn't Work
In the monitor OSD, navigate to 'Game Settings' and manually set 'FreeSync' to 'Off'. The flickering will stop, but you'll have standard V-Sync input lag or screen tearing.
Heads Up
This flicker is a hardware-level characteristic of many VA panels in VRR mode; it's not a defect. It's most noticeable in loading screens or poorly optimized game menus where FPS tanks.