I bought a new Kuruma Zeta spoiler to replace my old one. I test fit it on my car and it was nice and snug. Then off to paint it went. It's been prep'd and painted. The next day when inspecting it, it looked to have 3 small cracks in the paint that run on from front to rear (not length-wise). My friend sanded it down again and painted it again. Once again the cracks came back in the same spot.
Is there some special prep that might have been needed here? This is a pro shop.. not a backyard type operation. Just wondering what might be happening and what is the correct way to fix this?