Mysterious Islands were not the best-thought-out addition to the game, but unless it’s an immediate effect and/or specifically says otherwise, the roll only applies to the specific ship that rolled it, and only to next time that ship does the action specified (explore, move, etc.).
My argument is that it effectively does say otherwise, by not specifying anything when it actually needs to for clarity purposes. “After exploring this island” is ambiguous compared to “After this ship explores this island”. The islands are from the same set and it’s the same type of game piece, so if they wanted to make them the exact same specification, the ability text should reflect that. I feel like it should be played as written, especially because there are so many cases like this throughout the game that will otherwise expand the Pirate Code even more if I have to keep bringing them all up for clarification. As written, the most logical interpretation would be that it’s after any of your ships explores the island, but probably just the next one that does, not for all future friendly explores of the island (since of course each ship that docks has to roll for effect).
MI #9: 5-6: “After this ship explores this island, swap any number of treasure coins taken with an equal number of treasure coins chosen randomly from other wild islands.”
Is the choice of wild islands you take from random as well, or just the coins themselves from island(s) you pick?
It’s also a bit odd that the quantity is ambiguous – “any number of treasure coins” implies you could just swap one (except for coins being plural), but the plural nature of “from other wild islandS” makes it seem like you might have to swap from at least two other wild islands, therefore upping the minimum coin swap count to 2 coins (which might not be possible if there is only 1 coin/WI available).
Based on this Code line from Intermediaro’s entry, I assume that you could use the above swap ability to swipe gold out from under a fort, even if that was the coin satisfying the gold cost of the fort?
You may take treasure from an opposing fort even if the total gold value remaining on the island would be less than the gold cost of the fort; if this occurs, the fort remains in play and continues to function normally.