This happened to me frequently when crafting redstone for auctions. I'd start with blocks and end up a dust or two short. I've finally tracked this down using iron blocks.If your inventory is full, crafting may result in some items vanishing into the void.Here are the steps (I've done this three times)a) Fill your inventory with stacks of something, like cobble.b) Leave 6 slots open.c) Grab a stack of 64 iron blocks.d) Open inventory, then "speed craft" the iron blocks into ingots. (shift-click the ingot crafting)e) Observe that 6 stacks of 64 ingots are crafted and 21 blocks remain.64-blocks = 576 ingots.21-blocks + 6x64 = 573 ingots.I am losing 3 ingots each time this happens. It looks like my inventory fills with as much iron as I can hold and the remainder of the division of an iron block is swallowed by the void.