[sfry]

DV,
I have been analyzing problems like this for 12 years. Your theorys are all correct. The problem could be caused by "compressed air humidity", Trapped solvent in the primer(too much too fast),poor airflow,fiberglass gassing ect.. We will never know until you pop one and look at it with a microscope. If you notice the height of the blister appear to be significantly higher than the surface. If you sand the blister until their flat than you will burn it. Remember that clear coat if applied correctly should only be around 2.4 mils.
Just my .02 and yes I did mean it need to be repainted.

However caution,depending on where the problem lies it might have to be stripped down the weak link.

Shannon Fry