Paint adherence on fiberglass door. Does it need time to 'cure'? Can I top-coat it?
I have lots of questions!  


Is the door installed in place?  If so, is there a storm or screen door?
Did you paint both inside and outside surfaces? If so: Did you use the same paint on both?  Are they both experiencing the same problems?


If there is a glass storm/screen door in front of the door, this could lead to problems with paint on the outside where the paint is trapped between the door and the glass.  If you could answer these questions in your question or as a comment, I can provide a more targeted response.  

This paint has a 4 week cure time and should will take longer to set if applied in higher than 60-70% humidity.

For expert advice, you may consult with a BEHR Certified Coatings Professional, call 1-800-854-0133 Ext. 2 in the US.