It happened again today, so experimenting with smart vent off, but the sunroof isn't my issue. I never use itI turned mine off (smart vent); but, I noticed that if you have the sunroof open (even just propped up) the car will automatically switch to outside air. You can turn on recirculated air, but after 2 minutes it will switch back to outside air. I read that part in the manual because I thought I was losing my mind. Not sure if that's what you're experiencing.