- The ingots now snap to the anvil, so don't stack them. There's a left, center, and right position on the anvil, so make sure that two ingots don't occupy the same location. Also, I believe that if the ingot is not snapped to the anvil in one of those locations then it will not factor into what you get from hammering.
- You're probably using 0.0.7 or 0.0.71, as getting the wrong material type after hammering was a common problem on those builds. This has been fixed in the latest version 0.0.72.