@jar.janca said there was a bug with the drops for mutated wolves and golems in a cave on an island of temperate biome, and they gave a Piece of Metal instead of Ylandium Dust. The next island, they dropped the normal loot.
We changed it a little bit Tiers 1 and 2 are now giving piece of metal, Golems ylandium crystals. Boss tier 1 and 2 give you a piece of gold and boss tier 3 ylandium dust.