I'm sure if your Audi sits outside, you've experienced this.

I had my car into the dealer for this and all I got was "Never heard of that happening." What I have found, though, is that Pam Cooking Spray on the door seals works pretty well. I'll give my wife credit for that, I prefer wd40 but my wife can't stand the smell and tried the Pam.

The only drawback is that you only know when the Pam quits working is when the door freezes shut again. On the other side of the coin, though, we don't use the rear doors all that often, so if the front is frozen shut, the rear will open IF we remembered to treat it in the fall.

YMMV