I don't have a photo of the side of the post, but I can say it is solid to the hull. Aside from the dirt you see in the pictures, it's a continuous sloping of fiberglass up to the underside of the rudder bracket.
I grease the ball joints each year, I had a friend with a 1998 340, who never greased his, and the fitting that wraps aroud the ball cracked and fell off. He came back to the marina using the Tiller. We replaced both fittings on his and greasing them have become one of the first things he does each year since.
Just a forgotten and least thought of area on a boat that shouldn't be. The friction caused the fitting to fail, you could actually see burnishing on the ball.
I say this because each year I move the rudder back and forth to grease it and in doing so you can see if there is any movement of the surrounding area.
From your picture, you can see the cracks you have are deep. For me, that would be a real cause for alarm.
Like the others have said in the post, check for any up and down or side to side movement of any degree.
Grease your ball joints also, (they look dry) that will help eliminate stiffness in the steering, which in turn puts stress on the entire system and "may" have cause the delamination you have.
I hope that's the case.