When window seals are compromised they allow ambient air between the panes of glass. The ambient air between the panes of glass is warm and warm air can hold more moisture than cold air. During the cleaning process the water on the exterior side of the glass may cool down the air between panes. Because cold air can’t hold as much moisture as warm air, the cold air is forced to release the moisture onto the glass. Much like the condensation on the exterior of a cold glass on a warm day.