Conversion fails if Hidden Power is in the first slot on Porygon-Z, which is a Normal-type, even if the Hidden Power type is different (in this replay, Hidden Power is Grass-type.) The only Pokémon that can learn Conversion are Normal-type, so without hacks it will likely always fail.
However, if it's used by a non-Normal-type, Conversion will change the user's type to Normal. In this replay Aegislash has Hidden Power Bug in the first slot.
Umm conversion with hidden power would= normal type which is useless even if you look at hidden power it is a normal type move
hope it helps :)
