Shift clicking in a stone cutter to craft cut copper slab from a single cut copper block will produce 8 slabs and move them into the inventory, but if the inventory is almost full and can only accept 1 of the 8 crafted slab, the other 7 slabs vanish (instead of dropping as items).
When performing the same craft with a crafting table, the other 7 slabs, that won't fit in the inventory, will drop as items.
Can confirm in 1.21 Pre-Release 1:
[media]Related to MC-206436