TL;DR Items can be duplicated by moving them into storage and then pressing "Cancel" rather than "Accept".
Setup requires minimum 2 of the same item. Place one into Storage as normal, Accept, and then re-enter storage. Deposit the second item, but exit with "Cancel" instead. Upon inspection, you should have 2 of the item in storage and 1 still in inventory.
This effect stacks with any number of items, The setup for this to occur only requires that minimum 1 of the item exists in both your inventory and storage. This can be done in reverse too, deleting items. If removing all items from storage and then "cancelling", upon revisit, Storage will show an item slot being shown with "Quantity: 0" of said item. Qty:0 slots do not physically take up slots, and will disappear after a storage transaction is "accept"'ed.
Also note that duplicating multiples will avoid any item stack limits until you finally "accept" a storage transaction, by then the item(s) will regulate itself into multiple max-stacks of itself. Exceeding your maximum storage capacity through "cancel"'ing will not hinder you until after you "accept" a transaction, thereby regulating items into slots and preventing ordinary withdrawal until Used Slots is ≤ Max Slots.
Setup requires minimum 2 of the same item. Place one into Storage as normal, Accept, and then re-enter storage. Deposit the second item, but exit with "Cancel" instead. Upon inspection, you should have 2 of the item in storage and 1 still in inventory.
This effect stacks with any number of items, The setup for this to occur only requires that minimum 1 of the item exists in both your inventory and storage. This can be done in reverse too, deleting items. If removing all items from storage and then "cancelling", upon revisit, Storage will show an item slot being shown with "Quantity: 0" of said item. Qty:0 slots do not physically take up slots, and will disappear after a storage transaction is "accept"'ed.
Also note that duplicating multiples will avoid any item stack limits until you finally "accept" a storage transaction, by then the item(s) will regulate itself into multiple max-stacks of itself. Exceeding your maximum storage capacity through "cancel"'ing will not hinder you until after you "accept" a transaction, thereby regulating items into slots and preventing ordinary withdrawal until Used Slots is ≤ Max Slots.