Same thing happened to me. 2013 S parked in the garage. A weird update last summer totally messed up the centre console screen and was pretty much unusable for a couple months. Then an update fixed that but made my home charging intermittent. Next update fixed home charging but added preconditioning, which I tried a few times in the super cold over the Xmas holidays when the car was outside. But then a couple months ago whilst parked inside our garage in town it heated of it's own accord to about the same temperature. The garage was a sauna. Tesla reported I set something to do that but I don't have any recollection of that. Suffice it to say I'm nervous about charging it indoors now even though I check it all the time!