Sounds like the primer sealer was sprayed on then the basecoat/clearcoat was applied 3 months later when the prime coat was rock hard, no adhesion between the primer and paint.
Usually like 4 hours max dry time on the primer sealer coat before you have to sand it again to get adhesion with the next coat.
Nope the can said wait 30 minutes then then then the base coat. It seamed ode to me because all the other sealer ive used said to wait 10-15 minutes before the base coat.