Concorde 04 Digital Thermometer

For the most part the Thermometer in my 2004 Concorde works fine; however, it has its strange days. For example, the outside temperature will be 85 degrees. When I start the car at 9 am the thermometer reads 65. It will remain at 65 all day, even after turning the car off and on several times. At 6 pm the thermometer suddenly jumps up to 85 degrees ... the correct reading. I once again turn the car off at 7 pm. At 11 pm the outside temperature is now 70 degrees but when I start the car it still reads 85 and remains there for the next 30 minutes before suddenly dropping to 70.

The dealer has replaced the sensor. Usually the temperature adjusts within about 60 seconds of starting the car, but I can't understand what makes it "sticks" on one temperature from time to time.

What is the normal refresh rate of this unit and why does it sometimes simply not work correctly?