Auto body repair & detailing: Section of paint turns white when wet!, low voc paints, water droplet

Question
Back in 1992, my father bought a brand new, blue Cadillac.  I was with him when we drove it out of the dealership.  The car has never been in an accident or had paint or body repair.  My father kept it immaculate and waxed. It was garaged about 95% of the car's life and the finish still looks great.
I bought the car two months ago.  I have had the car outdoors on my driveway.  One day, after a few rainy days and some humid weather, I noticed a very pronounced section of the upper rear drivers side door looked almost white when it was wet.  It was directly under the pinstriping and about 10 inches square.  It seemed to only affect the door.
When it dried, the finish seemed to look normal again.  I recently washed the car and it almost seemed worse.  Once again, every water droplet on that area left a white spot!  I waxed the area thoroughly thinking it would help but even after waxing the water droplets make it turn white when it gets wet.
Upon closer inspection it almost looks like a slight ridge of paint under the door handle, as though a layer of paint had been stripped away around it.  I never noticed this before.
This change all happened very suddenly, it was fine one week and now this.  It seems strange after 15 years it would change in one week.  What are your thoughts on this?  Could someone have vandalized the car? Is the rest of the paint job in jeopardy?  Should I have a body shop look at this? How would this be repaired?
Thanks for any help you can give.

Answer
Hello Mark! The Caddy has a previous body repair, and it's starting to fail. Back in the early nineties, refinish companies were fooling around with low VOC paints, and the early attempts weren't very successful. I suspect that the clear is starting to fail because you are subjecting it to much more sunlight than your father did, and the sun is starting to attack the paint. The body filler may also be starting to fail, or the peroxide in it is starting to bleed through. I've seen cheap body filler actually turn the clear coat yellow everywhere it was applied. This was mostly on white cars, however. Take it to a body shop for an assessment, they will be able to tell more by actually being able to see it. Without seeing it, I'm just making educated guesses. Bill