"Mud cracks" and "it chips away right back to the glass" lead me to believe that what you are seeing may be a case of failed chemical bonding of the
gelcoat to the laminate in the
mold. This is fairly common, the manufacterers just wait a little too long and lose the chemical bond, often in a particular area where the
gelcoat cured too much before being laminated on. I've seen cases where the whole
boat was like this and cases where it was just a small area. If it really chips back to the glass and not the gelcoat this is the most likely scenario. If it chips back to gelcoat, it's probably because they tried to use a non-sanding primer when they commissioned it and this is causing the barrier coat to fail; much less likely. The "mud cracks" could also be a sign of gelcoat alligation, either in factory gel laps or in a
repair. When you chip it off, do you go back to clean glass with no gelcoat at all on it? Some pics would help. If you want to do an adhesion test for paint, the standard method is to really rub on some duct tape in a big patch and then cut an X in it through the paint to the substrate. Then pull the tape aggresively. If paint flakes off around the edges of the cut the adhesion test failed. If you end up with a nice clean X cut in your bottom paint it's good.