As you can see, it is a strip-built kayak, certainly less than 30 years old, where the epoxy and fiberglass is delaminating.

I don't know if your correspondent checked (by sanding and smelling?), but (as you know) lots of strip canoes and kayaks were built with polyester resin 'back in the day'.
In the 80s I worked with a top-ranked marathon canoe paddler who used an old race canoe for solo training with a couple of concrete blocks to replace his partner, who lived in a different part of the country. I recall noticing some 'whitish' areas (probably delamination) on that boat. One day on L. Ontario, my friend paddled over a wave and the boat broke in half! He got to shore OK.

Shortly after that I sold him a strip epoxy marathon-style boat I'd built from MCA plans. :-)