Agree on Sync not on Auto exactly and similar behavior in my old Odyssey. The priority with AUTO seems to be to keep the Windows Clear of Fog and that is where most of the Fan and air noise are. I just tried this in my Palisade at 35 degrees F /61 percent Humidity and a couple minutes of idle and local drive and used Auto. You can hear the fans kick over to by the Dash front windshield. As soon as I changed the temp or flow back to me I had heat. As soon as hit Auto it returns to working on the windshield. If I recall from the manual it uses a combination of heat and AC to to Auto keep the windows clear. Of course it can not "see" the windows. Well I do not think it can lol

It does watch the driver's attention.
In short there are so many variables, Humidity, inside temp, outside temp, windshield temp, distance of front passengers to windshield breathing on it, engine temp, etc.
-I do not think we can expect warmth of passenger to be the 1st priority. I will also say I have always hated Auto in other cars because I like the fans on around 1 or 2 out of 5 or they make too much noise. Auto tends to keep them around 4/5, Noisy and usually goes for the wind shield vents. Also I had no fog on my windows when I changed it back to the way I wanted.... Fans on me
