Single-player: no mods
King Elk Trophy Heads keep disappearing from inventory.
Got a Trophy, put it in my tannery station.
Went and got another of the same kind - came back… it was gone.
Went and got another Trophy, of the same kind - no problem, they both stacked (2) in my tannery.
Logged back in… and its not there.
note: I have no idea when they went missing… I did take all items out, and replace them, to organize.
(no, I did not accidentally drop anything - but I may have overlooked that taking all the items out is when it disappeared… since Im not expecting items to go missing.)