That does have the general look of water damage.
What troubles me is that the tabbing has not only seperated from the pad, but has dropped down below the level of the pad.
It may be more than the pad getting rotten and squished. The deck core may also have gotten soft and the two skins are crushed together.
I would go ahead and cut away the tabbing, which serves no real purpose anyway. I would also drill some test borings into the underside of the deck. Just carefully pierce the lower skin and see if the drill produces balsa shavings or mush. The area between the pad and the forward hatch hinges would be most suspect.
Scrape the paint off the metal plate and see what's going on there.
Not much else you can do until the mast is unstepped.
I still wouldn't consider any of this to be a safety issue.
I have a bit of concern about the compression post on my boat. The steel is partially corroded where the post goes through the cabin sole. I don't know how to fix it, so I'm gonna ignore it.