Made 4 backpacks.
Inventory of backpacks 3 & 4 share the inventory of backpack 2.
When placed in the world, they have 4 separate inventories, fully duping the items from backpack 2.
When picked back up, the inventory of backpacks 3 & 4 share the inventory of backpack 2 again.
This overwrites the contents of 3 & 4 in-world-inventories.
Inventory of backpacks 3 & 4 share the inventory of backpack 2.
When placed in the world, they have 4 separate inventories, fully duping the items from backpack 2.
When picked back up, the inventory of backpacks 3 & 4 share the inventory of backpack 2 again.
This overwrites the contents of 3 & 4 in-world-inventories.