Brake Question?

Both my Audi’s, S4 with Brembo’s all around and my SQ5 have been subjected to ice, snow, salt and slush recently. The SQ5 just Monday in CT to the blizzard.(?) The SQ5 is a completely stock vehicle. Best cruising car I’ve ever had. Regardless, both are now in the relative warmth of NC. However, when first moving the car after parked at night, in a garage, the front brakes are emitting, both cars, a rubbing or very light friction like noise until the cars goes through several brake applications. Sound seems to be from front end on both vehicles. The rotors are clean, smooth and rust free. Any ideas? Thanks.