I'm also curious about another issue that could be part of or contributing to this. When mine had about 7k miles on it, I noticed that water was entering the lift glass somewhere on the top, as it was dripping down the inside of the glass. The answer from the dealer was to replace the weather stripping around the liftglass, which seemed to help (but also super annoying given this thing was basically brand new). But the reason I bring this up, is that if water is getting in the spoiler area enough, in these nasty temps, it makes great sense that it would freeze and cause issues like this.