When I put one SPRUCE log in the furnace burning slot, then one stack of OAK in my inventory, and then shift-click on the charcoal in the furnace recipe book, I am left with one oak log in my inventory and 64 spruce logs in the furnace slot. I expected nothing to happen.

This happens both in creative and survival.

To reproduce: 1: place a furnace and have two types of log in your inventory(both less than a stack)

2: place one type of wood in the furnace and keep the other in your inventory

3: click on the charcoal entry in the furnace recipe book