I agree with Jeff's advice. I don't think this is unusual, the Moody yachts had a recess for the keel flange to fit in, but it is definitely not precision engineering and there are fairly substantial gaps around it, which are filled with sealant. As the boat gets older the sealant loses it's flexibility and shrinks. Often needing to be raked out, dried and replaced. Hopefully this is just the sealant around the outside of the keel and is not breaking down on the hull to keel flange joint. As Jeff says, check internally and point out to your surveyor.
Paul