[kitcarbp]

Well its not about how or what gas you spill on it. This is a defect in the paint materials and the process used to apply it. The type of filler cap is the least of all worries. Mine is vented and after a full top up (top of my filler neck) it weeps a bit of liquid around turns sometimes. It gets on the paint sometime. I used a basic PPG paint system on the car with modern clear coat. Sorry to see this. This is an issue for Backdraft Paint Quality department to address. Modern clear coats are engineered to resist typical automotive chemicals including gasoline and E85 and the E blends in between. Even water based paint systems. I would guess this is not the only car suffering from this defect if it was painted by the manufacturer. Hope they step up to help you and stand behind their paint job. Really a bummer.