The problem is caused by the lack of gelcoat on the thin bottom edge of the lids. Moisture wicks up into the substrate, freezes and pops the filler used to build the panels. I found very minimal glass in these panels and many voids (which hold moisture)in mine when I ground the edges out in order to find solid material to build against. I layered up lots of glass and resin, like it should have been done. I wrote a post about rebuilding them a few years back, but photobucket has disabled the pictures. I had problems with all the hatch edges and pulpit. The inside core was found to be a Masonite type of product which turns to mush when it gets wet, expands and cracks the putty filler what ever it is (not resin) as well.
That seems to be a problem with many Grady’s from late 90s into mid 2000’s.
You either need to learn to repair or pay $$$, but if not done well, will happen again, don’t ask me how I know that.