DIAGNOSIS The QuickFit virtual scale/alignment grid is activated and locked on. This occurs when the dedicated QuickFit button on the monitor's rear bezel is stuck in a pressed position or the OSD setting is corrupted.
FIX First, locate the physical QuickFit button. It is a separate button on the rear bezel, below the joystick, with an icon of a rectangle with a crosshair. Press it firmly once to toggle the QuickFit overlay off. If it does not respond, press and hold it for 5 seconds. This should force the function to cycle and disable.
IF THAT DIDN'T WORK Perform a factory reset on the monitor. Use the joystick: navigate to Menu > System > All Reset > Yes. This will clear all user settings, including any corrupted toggle for QuickFit, and return the monitor to its default state. The QuickFit overlay will be off by default.
HEADS UP The QuickFit function is purely an on-screen overlay and does not affect the actual video signal or saved files. It is only visible on the monitor itself. If the physical button is mechanically stuck, you may need to have the monitor serviced to prevent it from randomly activating again.