When Crafting an item that consists of only one item,the item in the crafting table will not be consumed

What I expected to happen was...:
Will consume the item.

What actually happened was...:

The item won't be consumed.

Steps to Reproduce:
1. put a diamond block in the crafting table(the item must be in the middle of the crafting table)
2. take the diamonds
3. the diamond block isn't disappered!