With multiple wood types in an inventory if you insert a type listed later in the inventory the first wood types amount is decremented.

I believe what should happen is that the inserted type be decremented rather than decrement the first wood type in the inventory. Although be careful as you fix this as I suspect it is linked to the "wooden plank" routine which also decrements the first available wood type in the inventory. Tested on two different Android devices.

e.g.

Inventory slot 1 : 5 Oak
Inventory slot 2 : 5 Pine
Inventory slot 3 : 5 Birch

Insert Oak : 1 Oak in furnace
Remove Oak
Insert Pine : Pine in furnace but Oak quantity is now 4
Remove Pine
Insert Birch : Birch in furnace but Oak quanity is now 3
Remove Birch