Due to:

1. Paint film too thick.
   
   
2. Painting on a very hot surface.
   
   
3. Subsequent coat applied when previous coat not dried.
   
   
4. Substrate surface contamination.
   

Recommendation:

1. Apply paint according to manufacturer recommended spreading rate. Painting two coats to get the dry film thickness is better than applying one coat to get the required thickness.
   
   
2. When applying paint during extremely hot, cool or damp weather, allow extra time for the paint to dry completely before subsequent coat.
   
   
3. To encounter this problem, wrinkled surface must be scrapped and sanded before repainting to avoid adhesion problem.