Samsung Note 9 Display Problems Please Join only if you are facing the Display discoloration or Overheating or horizontal lines on display when the brightness is set to low. All these issues are started recently after software update, not by any accidental or physical damage to display.
i just found a temporary solution for the green screen.. just swipe down and you will find "always on display". turn it on.. that would be enough to stop the green screen from coming. it only comes when you lock and then unlock your phone.. so this would eventually keep your phone screen on all the time.. so try this ! :)