ok so I thought I fixed it but I didnt, Even when selecting the correct amount of Total Stacks when you drag the items into a furnace slot or any other items that can smelt, you lose ore's / materials.

Example if i select 2 total stacks for the furnace as thats what the new UI as for Rust, If i left clcik and drag ore over to the input slot i makes some of the material dissapear. So if I say I put 10k Suplur into furnace well if I dont smelt it and take it back out i can lose around 2k of sulphur each time.