What happens when a special wound token or a wooden marker cannot be placed because one is already there?

Question

Accepted Answer

A special wound token that cannot be placed gives the character one normal wound. A wooden marker that cannot be placed triggers Unfulfilled Demand and causes wounds, while an ordinary cardboard token that cannot be placed causes nothing.

Robinson Crusoe: Adventures on the Cursed Island

What happens when a special wound token or a wooden marker cannot be placed because one is already there?