Temperature sensor faulty? And noisy heater?

[ElectrikFred]

This week the UK has been cold….approx -3 to -5 degrees C

However, my M3 Standard 2022 says that it is -13. Eventually (like 30mins post driving) it gets to the likely real temperature.
anyone else seen this?

Also, the car heater makes a much more audible noise - even on fan setting 2. Again I have only noticed this in the last few days when it has been cold.

I have been using the DEFROST option for approx 5mins before starting the car

Any shared experiences or thoughts?

cheers