Might want to inspect your brass tubes while you are at it. They do fail over time from corrosion and could leak into the core. Here are mine after 18 years...
I have a 2008 2120 with F225 on the back with a very similar gelcoat crack. As far as I've been able to tell, the transom is solid and no structural issues going on. I scraped the gelcoat along the crack to widen it and filled it with epoxy. Plan is to cover it over with a fresh layer of gelcoat one of these days. Thinking maybe sometime this summer I'll get a can of Parker exterior gelcoat and give all the little scuffs and scratches a once over.