To recreate, fill all inventory slots with items other than torches. Each slot does not have to be at max capacity, but does have to have an item. Place some torches in off-hand, but do not max out the slot. Place a torch and hit it to make it fall on the ground. Once it has stopped moving, if you walk over it, you will not be able to automatically pick it up. Note: if you stand close enough to catch the torch in the air, it will be added to your inventory, but if it hits the ground and has stopped moving, you won't pick it up automatically. Also, to pick it up at this point, you can stand over the torch, open your inventory, pick up the entire amount of items from one inventory slot, and the torch will be picked up and added to off-hand slot automatically.