Although the LCD monitor is manufactured with very high precision technology with over 99.99% active pixels, there might be a few dead pixels among the remaining 0.01% or less pixels. Dead pixels displaying only black or red, etc., are not a malfunction. They do not affect the images recorded.
At low temperatures, the liquid crystal display response may be slower to respond. And at high temperatures, the display may blacken. In either case, the display will return to normal at room temperature.