Of the three steel artifacts made by the dwarven artificer, the crown and amulet ("steel crown" and "steel amulet") are made of iron, but the shield ("steel shield") is made of mithril. It would make sense if they were all made of iron. Like this issue, it only affects mist elves because the items in question are artifacts, but it certainly wouldn't hurt (and it certainly wouldn't hurt mist elves) to have more consistency so players playing mist elves don't have to wonder why the shield doesn't burn their skin while the crown and amulet do. Other related issues (this one and this one) also affect consistency, rusting and smithing for all races.