Inside of a crafting terminal, any one block recipe (such as stone -> stone button, or diamond block -> 9 diamonds) can be placed in the terminal, and the crafting output can be shift clicked or regular clicked infinitely without the item placed in the crafting terminal disappearing. In a matter of minutes I was able to turn 1 diamond block into 9 chests full of diamond blocks.

Okay so on further inspection it is actually taking items from the storage but it is still duplicating. For example I have 8k zinc ore in the storage and nothing else. I place one diamond block in the crafting terminal, and shift click the diamonds in the craft output and it will fill my inventory with diamonds, taking away that number from the zinc in the storage. However you of course can just do it with zinc/ whatever item is already in the inventory and then do it infinitely.

I think this was fixed here 09533a1#diff-f80f6f34b5a97a2a34c2be31f4a65852530ff8250f6cdaf43af59a3b1d567f98

But not for older versions of Fabric like 1.20.1

Do you have Create belts touching your storage system. Create Fabric Belts have a dupe bug, they'll let you extract any item without validating if the belt actually has that item.

I have been trying to reproduce this and didn't realize that that was a think but it makes sense. Since Create chutes and belts technically are inventories then they connect to Tom's if you use the feature where adjecent inventories connect. I think I am able to reproduce this without a belt but there are definitely a lot of Create things touching the inventories that could be the root cause. Will try to narrow it down.