Anyone had a occasional issue with the outside temperature gauge reading something like 1.5°C with the frost warning on when it was actually 20°C or more outside?

I've had this on about 3 occasions. It gradually corrects itself of you are driving for long enough.

Recently had the car serviced (9000 mile oil change) and the dealer said it was a software issue that they were waiting to receive a fix for.
As a goodwill gesture they filled up the Adblue tank FOC, which I was happy with.