(Redirected) UP2715k split screen

I have had the display for 18 months.  The right hand side of the screen has recently shown a different tone/colour from the left.  It has been 'reset', no change.  

The fault appears with the following setups:

at 4k with the mDP cable connected at Windows login and with Windows loaded;

at 5k with the two DP cables connected at Windows login and with Windows loaded using the 'standard' setting in 'manual' mode.

At 5k the fault is not present when the display is set to the following modes:

Adobe RGB, CAL 1, sRGB, CAL 2 and Custom.

The fault persists after reinstalling the latest nVidia driver. 

The display has been connected to the motherboard with the mDP cable and the graphics card removed, no change.

Windows 10 1709

EVGA GeForce GTX 970 SSC GAMING

Gigabyte GA-Z170X-GAMING