Did you stand on the deck in front of it and see if it creaks or bounces if you hop around a bit? Also, knock on it with a piece of timber or your knuckles (might hurt a bit on the non-slip - have to knock fairly hard when using knuckles). If the area sounds hollow compared to elsewhere, it may be delaminated.
The core is closed cell foam, so the damage from water ingress is very limited - it will not rot or absorb water and delamination can be repaired (although difficult here as AFAIK no access from below in that particular area and top is non-slip patterned), but it's certainly something to show the surveyor and a significant factor when deciding your bid.
If it doesn't bounce or sound hollow, it's probably fine and just needs a bit of gelcoat filler. Maybe something heavy (anchor?) has been dropped there once.
