Display Enlightment by NCX

I swapped to the Ultra Fast setting again and the obvious white trailing is gone?
Is this normal behaviour? Does a monitor need some sort of warming up?

It could be a firmware bug, also, some of the View Modes such as the Text Mode locks the Response Time setting to the default Fast setting.  Were you viewing the same content (Test UFO Ghosting Test) when you noticed the lack of or presence of overshoot? 

When panning the camera at 60hz the grey circular Traveler in Destiny 2 (30 FPS on the PS4) suffers from a tiny bit of dark transparent overshoot ghosting when the sky is blue.  In game motion blur tends to increase overshoot ghosting.  Many monitors struggle when white and light blue; try dragging this screenshot from the Overwatch map Illios and pay attention to the giant statue and white clouds.  I have not done this yet but will be tomorrow, as well as more extensively looking for overdrive problems.