Different, lots older Subaru here, but when I was snowboarding a lot a few years ago, I usually rolled a window or two down to help the moisture dissipate. Mine lived in an unheated garage. Never had ice on the inside of the windshield, but did have some condensation now and then. If you have to park on the street, maybe you can crack the windows a little bit.
If that doesn't help, try opening a case with Subaru USA.