I'm combining smelted ingots from 3 separate furnaces, with 1 crafting table in front to make blocks (to store easier). I use SHIFT-CLICK on crafting options from table to make all the blocks at once, instead of furiously clicking... I have a mouse and no touch-pad, so I'm positive I clicked only once per ingot type. 

After I successfully turned (copper, gold and iron) ingots to blocks (my inventory then after looked just as it should), then I placed blocks into chest next to furnaces/crafting table.

I then noticed after opening inventory, a few moments later, that I had 63 Oak Buttons and 60-something Levers!

It had ate all my Cobblestone, Sticks and Oak Planks!

I'm positive I didn't double/triple click, as I was looking at inventory, placing into said chest at time of condensing.