Building steam rocket engine deletes steel

I produced over 2000kg of steel needed to make the rocket engine ( not sure if I had 2100 or 2200kg, but somewhere around there ), and the icon lit up indicating I had enough material to build it.  I started building it, and after a while, ran out of steel with 800+ kg left to go.  I built nothing else with steel during this time, and I'm pretty sure I even refined one or two more batches thinking I would need more for the research modules and command module.

The Radioactive Panopticon.sav

The Radioactive Panopticon Cycle 1063.sav