This is likely the monitor's Flicker Safe feature or a low brightness setting interacting with the panel.
First, check your brightness setting. Very low brightness levels on some IPS panels can cause perceptible flicker. Increase the brightness via the On-Screen Menu.
This monitor has a 'Flicker Safe' feature designed to reduce screen flicker. However, the implementation can sometimes cause its own subtle fluctuations on certain colors. You can try turning this feature off in the On-Screen Menu under Picture > Flicker Safe to see if the issue stops.
IF THAT DIDN'T WORK: The issue could be signal-related. Ensure your video cable (HDMI or DP) is fully seated at both ends and is of high quality. Try a different cable or port (switch from HDMI 1 to HDMI 2).
HEADS UP: If the flickering is severe, constant, or accompanied by colored lines, the panel or its controller may be faulty.