RE: Fiberglass Cowl/Pin *****s
Sounds like a condition called "fish-eyes" ------ simply because that is what they look like.
I have had the same experience. The cause------you wont want to believe this------is surface contamination, probably oil or silicone based----or some of that pesky release agent from the molding process.
You can go to an automotive paint supplier and they have silicone removal agents, probably more advanced stuff than I am familiar with, as one small can lasts a LONG time with model A/C.
Next you can do the perfectionist's routine, and strip away all your primer so that you can clean and shoot again. (been there, done that)
Or, after you reconsider, wet sand the areas with the silicone removal fluid as the wetting agent and spot prime until you are satisfied . Then fog a complete coat of primer on the cowl or since you are using black for the color coat just shoot it with black.
Unfortunately this is a rather common occurence.
Having done it both ways, the wet sand and spot prime is definitely the way to go !!
Have a Merry Christmas.