Try to check if the exhaust of the aircon is closing or not, below the windshield, remove the black color plastic cover on the right side and from there you can see and check whether it is closing or not.
Mine too, 2015 fortuner, noticed this 1day after owning. May papasok amoy usok or baho sa labas pero sometimes lng talaga mangyari, may certain angle siguro na papasok amoy. Kahit naka circulate na vents
It may be variable speed I think. It's slowly being used on cars that either don't have an ICE, or...
A/c