But I would guess that they probably happened after glassing the
: outside and before glassing the inside. During this time the inside has a
: chance to dry out or absorb moisture which can cause some movement in the
: wood.

You
: might be able to fill in the hollows with multiple coats of epoxy to make
: it smooth again.

I agree with Nick, it probably happened before the inside was glassed.

I had the same thing happen on a boat.

I added a couple strips of glass over the area to build resin depth quickly and sanded it flush with the surrounding area.

If you use a slow hardener or wet-out resin the extra glass will be very transparent and only you will know there was a problem.

All the best,

Rob Macks
Laughing Loon CC&K
www.LaughingLoon.com