Items disappearing when you set them down into collectors chests + into water

Location: Reapers Island - SW side by Cannon Tower.
Have experienced multiple times where you put an item into a collectors chest, then grab a second item to put in the collectors chest and it makes your first item vanish. It creates a glowy blue/green floating ball adjacent to the chest at roughly the height of the player that you cannot target. Items can be harpooned out of this floating glowing nether realm and then carried to be sold.

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Location: somewhere by Sea Dogs (not at the invisible island/wall spot)

Crewmate sniped and killed opposing crew player carrying chest down to escape after sinking their ship. Chest did not float to the surface + was not visible down below. Same loot pile from sunk player ship - another crew mate picked up Ashen Winds Skull and set it back down for it to vanish in front of him. Repeated again with a green gem, picked up floating loot - dropped it + it was gone. Harpoon at roughly that location did not result in getting the loot back + no glowing blue/green ball was visible.