Well i was playing in a private shard (3rd person) server with my friend and we decided to leave some food, a gas lamp, a vest and a backpack inside a house in a lonely house. after we leave to drink some water of a near pound we went back and we didnt find our things. There was new loot inside the house and the backpack was invisible, my friend was able to saw the backpack but i dont after a fast relog i saw the backpack (full with ammo and attachments) but the items we leave with the backpack disappear (all the food, the gas lamp and the vest) and was replaced with new loot over the place.

The weird thing is that the server doesnt even restarted and i was able to see the door of the house all the time so it wasnt another player (just 3 players on at that moment)