The bug
When a user has items on the crafting bench, and they select a recipe that doesn't include those items, if they have enough free inventory space, the items will be returned to their inventory, and the new recipe will be selected. If their inventory is completely full, nothing will happen. However, if the user has some free space, but an insufficient amount, only a portion of the items will be returned, and the rest will cease to exist. Expected behavior would be to drop the overflow on the ground (see MC-1555) or to have nothing happen, like when the inventory is full.
How to reproduce
Set up your inventory and crafting table like in the attached
- [media]
Click a recipe like sticks
[media]
→ You will see that only one of the stacks of diamonds is returned to your inventory.
Are you using creative, if it is, then it's an intended feature