Tooltip (or whatever is it) showing when other player changes toolbar slot.
I discovered this bug after the frostbite update. I was playing with my friend (not on DS) and if he presses 1,2,3etc... to switch items in his hotbar mine will display the tooltip for the last item I was holding.
1.Have a friend join your game.
2.Put any item in your hotbar and then remove it or press 0 so there is NOTHING in your hand.
3. Tell your friend to hold ANY item in her/his hotbar.
4.The tooltip for item you were holding previously will appear.
Edit: I don't know if the same happens on dedicated servers.