I've noticed the same issue - outside temperature was in the 50s - but the car, inside the garage, while charging was in the 90s.
Overnight, when charging has been completed for several hours, the inside temperature is pretty accurate.
NOTE that this problem has been present in my ICEs with exterior temperature displays - they often didn't register the correct temperature, especially after the car has been sitting immediately after driving, when the engine heat warms up the car until everything cools down.
My bigger disappointment is about the temperature setting on the climate controls. In order to get the car cooled properly, it typically requires setting the climate controls to 67; but when heat is needed, I manually increase the temperature to the low-to-mid 70s.
Based on the outside temperature, I wonder if a software setting could be provided to correct for this and properly calibrate the climate control temperatures to be more reasonable...