I have a row of furnances … when trying to add more, x2 disappeared when trying to add more furnances to the others. Those furnances had full amounts or near full amounts of raw sathium and/or iron. I think one had iron and the other had sathium based on what ive been trying to change to ignots.
I dont think it was structural integrity though, it was already spawned and smelting ignots, it was when trying to connect another one in, and it was touching the ground which should give it structural integrity.