After a gun fight, and return to like Aim-120, the radar of F/A-18C inverted the horizontal and vertical axis. So what you will see is the now the arrow for radar elevation is moving up and down, and it's range can be control by the the degree setting on DDI like 40°, 60°... And the vertical line moves now as how the radar elevation arrow usually did, If the setting is 1B1, then it is stable and if the setting is 2B1 and 2B2, it will jump between 2 position.
I have attached a video for that, this happens at any map, and always after a gun fight kill, and switch back to BVR.
DCS_bug1.mp4