Yep, there are patterns to most every failure. When you are dealing with problems every day in shops all over the place as when you are in the paint business there are patterns, they are so obvious it isn't funny. Same as in the collision business you can look at a car and tell the owner how it happen before they tell you, there are patterns that because so clear and cut and dry it isn't funny.
This one most certainly doesn't fall into any one common pattern. It is odd, after seeing failures day in and day out for years and you don't see something like this I can see it being in your mind non stop Barry, it is an odd one.
I still can't see it being anything but the perfect storm.
I remember I laid a stripe on an S-10 truck once, it went all the way around the truck in HOK candy. Now thinking back my mind gets cloudy on just what the problem was, but it was peeling or severe die back or something. Anyway the failure was directly related to a time issue, where as the portions of the stripe that were applied over the primer the soonest failed where as the stripe over the primer that last applied worked fine. It was as clear as day that the application time had EVERYTHING to do with the failure. All within one stripe! So the planets can be aligned on one area and not another.
Then stuff comes out of blue. I had a Ford truck that failed BIG TIME. We are talking a SS acrylic enamel complete that was striped to bare metal and primed. Sealed and painted, about a year later he came back and the paint was CHAUK! You could literally put your fingernails into it like a bear claw and scrap the paint off with your nails! Now the odd part, it was a color change. The door jambs and underhood were all perfect! Then it hit me, I had a test panel that I had painted and thrown up on the roof. I went up there and got it and you guessed it, PERFECT. WTF? I did a little detective work and found out from a friend of his (we are talking detective style fact gathering here, the guy didn't rat on him) told me he had waxed it with a sealant style wax at just a month old!
I refunded him his money but wasn't about to repaint that truck.
Every odd one, if you are there looking at it and are able to ask many questions and SEE how things are done you can usually figure out even those odd ones. And it's an easy to get passion to figure them out isn't it Barry! You get a high tracking down the cause.
I can certainly see why it has been on your mind, it's hard to forget about one like this.
I am still thinking it is simply a perfect storm with just the perfect solvent entrapment and wax and grease remover soaking in kinda thing. Something made a "barrier" between that primer and paint! No lack of sanding could do that. You could paint right over an unsanded hood that was cleaned properly and not have it come off in sheets like that. There was a barrier, there was SOMETHING between the primer and paint, like a sheet of saran wrap laid over the primer and then painted on, there was something that totally separated the primer from the paint. No lack of sanding or hardener in the paint is going to do that! (I still will recommend never to mix products though). Nope, something is between the primer and paint, and the only thing this could be is solvent of some sort.