Yes, I can see the texture. It looks very much like what I have experienced when moulding directly off some polyurethanes without the use of PVA. PVA should have prevented it, though I generally spray 5-6 layers of it so that it, so I dont know if brushing on one layer would be enough if it didn't form a closed surface. My gut feeling is that it would still protect the surface, and so this isn't that same reaction problem.
Which makes me feel like it is potentially a heat issue. Perhaps the exotherm of the gelcoat curing got too hot for the paint to handle and it bubbled. But really just guessing now, there's so many possibilities with the various chemicals in play that it is quite difficult to know for sure.