I was hoping Jason would chime in here...I'm curious to see what he's got to say..
From what I can see, the Cherokee has bubbles mostly starting from rivet heads,valleys, and seams.... hmmmm. That always screams a problem with the prep in my book. The paint coming loose in the valleys of the surfaces is most likely a prep problem as well. If you look at samples of Stewart's Polyurethane that aren't attached to a substrate of some sort, you'll notice right away that it's the most flexible paint you can find! That is a good thing, but also demands that you have a good adhesion, both tooth and chemical to the substrate, as a flexible paint wont help itself stay formed to something as easily as a more rigid paint when dried.
The other bubbles look like solvent popping, from what I can see. Like has been said, it has to go on very light and let dry longer than more common solvent borne paints. It's also more picky on the mixing than the more common solvent borne paints. Like I said before, not difficult, just different! I've "been there, done that" and have some results just like this, hanging on the wall, to remind me. As soon as that underlying "gas" gets trapped, it starts lifting the skinned over topcoat that you've just applied (which hasn't bonded to the underlying coat all the way yet), and when it finally "pops" through the topcoat, you've now got a path for moisture to get under the topcoat.
One day we had some tail surfaces laying in the shop, drying, and one of the guys was on the other side of the hangar (60x60), and squirted a pulley with some tri-flow. The sun was shining and you could watch a little cloud of tri-flow migrate ALL the way across the shop and head right to those surfaces, just like a magnet!! Needless to say, we had a contamination problem with them when we went to paint them.... and from then out, nothing comes out of the paint booth until it's topcoated and dried. I was amazed that it took such a small amount and that it had travelled so far! It explained alot of previous problems I'd had too!
One of the things that I don't see mentioned much is airflow over or through the painting area. A booth that has no airflow isn't going to do you much good for getting the finish to gas out. It doesn't have to be a hurricane, but it definately needs some airflow!
Like I said, this is my 2 cents worth, and worth what you paid. Sorry to hear you both had trouble with the product. I've used it for years and love it!!
John