I had my car garged for the winter. only went out in salt once and I did a major detail on it but only put one coat of Klasse S/G on it. on the rear hatch area there is a bubble and obviously we all now its rust underneath the paint. When I did the major dettail it was 40 probally degrees out if not colder. I let car sit in garage and I remember seeing a water mark and I thought it was just frozen water on the rear hatch. So I left it alone and come to find out it was a bubble. Could it be that it was frozen water before and it just rustd up that area? I wouldnt think so since the car was in the garage. BTW this is a 99 black integra.