First of all this shouldn't be paint, but gelcoat. Since gelcoat cures by air inhibition or by blocking air from the surface, this usually entails covering the curing surface either with the glass lay-up in the case of the exterior gelcoat in the mold, or the interior layers of gelcoat that go over the glass lay-up have wax in the gelcoat that rises to the surface as the cure starts and seals out the air; or a layer of PVA (poly-vinyl alchol) is applied over the gelcoat which then dries and seals out the air. This is green in color and washes away with water. Now, all that said, I think what you have is a coat of gelcoat applied over cured gelcoat with insufficient or no prep, thus no adhesion value. The reasons for this are unknown, as only the gelcoat crew knows what happened. Typically, the gelcoat is applied in three coats, cross passed, to achieve 21 mils. This means three passes,first coat horizontal pass, second, diagonal and third horizontal. Each pass approx. 7 mils., with cross passing used to achieve uniform flow,coverage and thickness. I know that this doesn't resolve your problem, but hopefully this info is some help. Good luck.