jake,

the boat was previous painted with a 2 component polyurethan paint, but pretty sure it was grinded away.

the new gelcoat was applied on top of the old gelcoat.
the ship yard has no explanation for what happened.
havent seen the foam yet but it was not soft, it felt pretty stable... from the outside it was more like vacuum bagging... like all the air soaked out of the foam...

I asked now if the shipyard used any chemicals to clean the hulls...

its pretty weird that it just happened so close to all the surrounding repair spots which are just fine...