In the entire watch there are only very few tiny drops of lubricant and they wouldn’t migrate to the dial. I can only suggest a flaw in the dial making process OR excessive humidity in your storage.
One of my GS dials looked like that and the previous owner lived in Singapore with no a/c in his house. Maybe it’s just mildew growth and no more.
Local watchmaker could inspect but Patek is your best chance for the definitive answer.
Mike