My wife recently purchased her 2017 CX-5 Sport AWD. With the current cold temps in the Midwest, she is getting ice and frost on the inside of the windshield. I had a 2012 Mazda6 Sport and I remember having a similar issue. However, I do not have the problem with my 2017 Mazda 6 GT. I assume the issue has something to do with the way the air circulates through the car when running the heat. Is there a combination of settings when running the car that will prevent this from happening?