Video panning differences don't have anything to do with input lag. The only way fullscreen exclusive mode would change the appearance of video panning (bugs as

Video panning differences don't have anything to do with input lag. The only way fullscreen exclusive mode would change the appearance of video panning (bugs aside) is if it changed the mode of the monitor so the refresh rate matched the video frame rate (or equivalently used G-sync or Freesync to do the same).