I apologise if this bug was already found
There's this bug where when you craft any item, it will consume extra unnecessary materials only if you have 2 slots or more of the required material needed to craft that item. Here's how the bug occurs: If Slot A is full (max. 10) and Slot B contains less than the amount required to craft the item, crafting the item will make the game ignore Slot B and instead subtract the required materials from Slot A, at the same time consuming Slot B.
Imagine this scenario: I want to craft a nail, which requires 3 scrap metal. I have 2 slots of scrap metal – one is full (slot A), the other contains only 1 (slot B), so total 11 scrap metal.
By crafting the nail, the game ignores the slot B, since it contains less than the required material, and at the same time consumes it, then subtracts the amount required from slot A. Thus I will have only 7 scrap metal left.
Another scenario: I wanna craft a spear which requires 4 scrap metal. I have 13 scrap metal in total so I will have 1 slot with a full stack of 10 and another slot containing 3.
By crafting the spear, since the slot containing 3 has less than the amount required (4), the game will ignore and consume it and then subtract the amount required from the full stack. Thus I will have only 6 scrap metal left.
I've tested this bug with the spear, hatchet, rope, empty tin can and the nail and it produced above result. I assume that this bug applies to all other items as well.
Edit1: version 1.05
Edit2: This bug was present in the previous version as well.