Tome of Alkahestry has the potential to dupe items

Steps to replicate:

• Craft a new tome
• Fill it with redstone (may not even be required per se)
• Open a crafting grid
• Shift Click
• No Fuel is used

You can also dupe the tome:

• Craft a new tome
• Put in an autocrafting block
• Try to "fill" the book with redstone
  

Shift clicking from the grid also allows the duping of items, but not the tome.

You may want to look over the crafting handler extensively.