Steps to reproduce:
1. Put a stack of logs (wood) in a slot of a crafting table.
2. Take out one "unit" of 4 planks.
3. Place it into your inventory, and double click it.
4. Another "unit" of 4 planks gets put into your inventory,
the output slot of the crafting table is now empty although there is a valid receipe.
This isn't permanentely though, just take the logs out and place them down in the crafting table again.
Edit: Also, this would be a way to "cheat" wood, since the number of logs isn't decreased when you do the double-click and create planks that way. As seen in the screenshots.