Went to a ship, broke some chests and collected the items, including the chests.  Although the items were collected, my inventory is filled up and not with the items collected.  Then, broke a plank block from the ship and collected it (saw and heard getting sucked in.  Do not have the item.

See picture below.  Although I did get the items of the map chest, the items of the ship treasure chest, including ingots of various kinds, and both chest are nowhere to be found. 

 The items I have are supposed to be there, but there should be uncollected items floating around.  

Confirmed this by searching with nightvision in spectator mode.  Player absorbed the stuff even though no space in inventory to receive it.

One more detail: I had just logged into the world and dropped off a couple items before looting the ship.  Something about that may have left the inventory in an incomplete state at the start.