Brad – There are several issues that are potential problems: As has
been pointed out there could be a moisture issue, or a moisture +
combustion by-product contamination problem. Another contributor to
gel coat adhesion is the timing of the cure and laminate application.
It is not recommended to allow gel coat to cure overnight before
applying the laminate. The window for maximum adhesion (with properly
cured gel coat) is 45-minutes to 3-hours. If the temp was high enough
during the overnight period, the advanced state-of-cure of the gel
coat may have resulted in a less than optimum interface bond. The last
potential concern is the use of micro (or any other filler) in the
resin. This reduces the wetting capability of the resin and again
reduces the interface bond strength. I’m guessing you had all these
factors leaning in the wrong direction.

Bob