I drove my 2016 SV yesterday on a short drive, about 5 miles. I then drove the car home, put it back in the garage and plugged it in (L2). I went in the house, and just a couple minutes later I noticed a sound coming from the garage. The heat pump in the car was running. I checked the cabin, and the car was off, the HVAC was off, and the fan wasn't running. I checked on it again about 15 minutes later, and it was off. The LEDs indicated normal charging the entire time.
This is the second time this has happened. This time it was about 20F outside. Last time it was closer to 5F. Any idea why this happens? Is it heating electronics for charging?