I noticed one new message on my center display. In small blue letters, below the on/off symbol for HVAC control, it stated "Keep Climate ON".
I have never seen this before. I had turned on my Climate Control (using the Tesla App) about 10 minutes before getting in the S while on shore power. This message is a new one for me. However, once the cabin was warmed I turned the HVAC off. Looking at the TeslaFi raw data for that trip, the battery heater was on for about the first 5 minutes of the drive then turned off just about the time I turned the HVAC off.
The reported outside temp was about 16F and the interior cabin temp prior to turning on Climate with the App was 36F.