Orange peel

After you sprayed the epoxy how soon did you spray the filler primer? And how soon after you sprayed the filler primer did you sand it and coat with color?

Also, if this was a spray bomb filler primer and was dupli color it was most likely a lacquer based primer which is not compatible with a urethane system.... You can experience "die back" hazing of gloss or loss of gloss... and also lifting, or severe adhesion problems. You essentially put a catalyzed product down first (epoxy) a non catalyzed primer (spray bomb duplicolor) and then sandwiched it with another catalyzed product urethane paint. The non catalyzed product expands and contracts at a different rate than the catalyzed product in temperature differences. This is like creating a hard shell over a soft base... it will chip or possibly have zero adhesion what so ever. This is why you never mix systems and if at all possible do not use lacquer for anything anymore.