After the lunch stop, we went to the Tesla service center nearby, and even they observed the issue with nothing in the logs.
Driving around with an 8 month pregnant wife and hot air in the car isn't wise, so, we drove a couple miles back to the hotel and I powered off the car. An hour or so later, went back to check, and it was fine.
The advisor mentioned it could be a module or some weird firmware issue (and he said a new firmware would be rolling out to everyone this week - a couple of days before the mass v10 started).
I have my appointment scheduled for tomorrow morning at the nearby Tesla service center, and I'm sure they won't find anything either. I still haven't received v10 (maybe tonight, unless they blocked it due to my appointment), but will see what they say.