what might have happened is you got a some skin oil or other contamination on there, or you applied too thick a coat over a coat that didn't have enough time to properly flash or cure.
the only way to get rid of this completely is to sand down, reprime and start again but you can kinda work the area back with a dry spray method.
when i did my front lip this happened in random little spots when i used a rattle can primer to fix spots i had sanded through. put it on too thin ect..
what i had to do was take some random yellow i had that was the wrong color, and build up the areas with very light, dry coats.
you choke the feed on your gun way down and spray from a higher elevation than you normally do so the paint is almost dry when it lands.
apply several light coats like this to the areas and lightly scuff between coats.
then apply a light, uniform coat or two over everything to blend it out.