I'm expecting the worst but it's possible it's localized. I still haven't heard from anyone who has been inside the transom on this model boat. I'll know better Monday.
Surveyor was out Monday. Transom is fine. The starboard corner looks like a close encounter with a concrete piling to the tie down ring. Enough of an impact to compress the plywood underneath and crack the glass beneath rub rail.
My fiberglass guy looked at it today. Transom looked good. No swelling or cracks at corners of the sump pit. His advice was to fix up the crack and gelcoat, re-caulk the bang cap and use the boat. Monitor for signs of the transom moving (which mine is not). Interesting thing he said to me is that he doesn't want to replace a transom prematurely. They are too hard to take apart! Seemed like good advice to me from a man who just walked away from a $10,000 job!
Transom will eventually have to be done but not today! As a friend of mine always says: "They are all sinking. The only difference is how fast."
7/17/2022 - I opened the corner up. It obviously took a hit from a concrete dock piling or something else hard. Transom is fine. Impact broke the rub rail mount (no backing support). Bang plate is fine. The cement like filler that GW uses was broke up. Cleaned everything out. Made marine plywood blocking. Thickened epoxy and glass cloth. Tomorrow more thickened epoxy and glass cloth. Clean up for faring compound and finish.