I DID have one of those "36,000 updates, do not turn off computer" at a start-up about two or three months ago.
I honestly don't know when this color thing happened, but I've known about it for some time ... 6 mo to a year.
Never bothered me before, but I had occasion to talk to my bank the other day and I was with their IT guy for 15 or 20 minutes looking at the situation and it was determined it is with me and not with them.
might try unplugging and replugging the monitor just to be sure the connector is making good contact. And try reducing the brightness and/or contrast while looking at the color chart posted above, to see if the colors are present but just washed-out.