From my previous thread I ended up getting my Dell U2515H replaced as the power button stopped working.
Now I've had this replacement for a week or so. Sometimes I had issues where in games if I quit the game, it would get rid of the color preset I set my monitor to (usually 6500k or custom color)
I have no idea what's going on it's behaviour is so erratic. Yesterday I was using it all day with no changes the OSD color preset.
Now however it's got to the point that when I first start up my PC, or restart my PC it's ignoring the color preset and I have to reselect it again....