several things can cause that. 1 thing i would guess is a adhesion not sanded good enough should . What grit of paper did you use? My second guess would have to be contamination maybe someone had oily hands or you used the wrong thinner mineral spirits will not work on automotive paint you have to use a the proper thinner. And third would have to be to much catalyst the top is drying before the bottom can and as the gases escape it wrinkle the top layer.
So what you wanna do is wait a few day for a full cure sand the whole area to be painted really well wash with methyl hydrate. let dry. thin paint with proper thinner and then apply a very light coat let fully cure and then re sand entire area and then apply moderately heavy final coat .
If you find any imperfections in final product just wet sand them out.