@kenneth-mcgrew
"i see grass and barrels get drawn as i move towards" that is render distance. the visual range from which the items are visible. if i had the option on my PC i would max that out, because its big enough to handle the stress, consoles or smaller pc's might not have the power to handle that, so the render distance is fixed.
when i sail past a small island i will see trees first, then lanterns floating, then barrels, on which teh lantern now stands, then small rocks and last skeletons.
also all the "items" on the islands are fixed they do not "spawn in"
only animals, skeletons, chests/gunpowder "spawn" as they are interactable objects.
all landmarks do not. only the range from which you see them varies.
simple; you did not find the right spot.
yesterday i had to find a shaded hammock on a sandy beach, my friend found a hammock on top of the island and tried to trigger it with music. but as the voyage read Sandy beach, there was a second hammock, on the beach.
also on shark bait cove we had to find a shark statue on north outer ring,, what it does not say is that there are 2 identical shark statues on that island,, trick is to find the right one.
so you just didnt find the "landmark" of a dead skeleton with bottles around it,,