I just noticed the year of this boat. Around that time Ericson experimented with a technique where they did not use ''finishing resin on the last laminate counting on
paint instead. This resulted in boats that never fully cured properly and would leach out resin for years later. The boat I first saw this on was in fact an Ericson 27. If this is one of those boats then the problem can be worse than simply a poor bond between the core and skin.
Jeff