Everyone seems to be having the same problem with the ingots on the anvil not being used (place 3 on, make a blade with only 2). I noticed this on occasion too, but it only seemed to happen when I removed/repositioned ingots that had already snapped to the anvil. After removal, those ingots were "broken" and unusable. To everyone having this problem: once an ingot snaps to the anvil: leave it alone and you should be okay.