Not a bug Self-Status Moves: Y U NO WORK

[Mystik]

I saw a Kakuna use Harden, but it had no effect when my Gastly came out. Just because it's a normal type move doesn't mean it has no effect. It just has no effect on Ghost-types.

 

[MrHippocrit]

It's because normal type moves don't work on ghost types that it says that, it's nothing serious and should be fixed sooner or later. It isn't game breaking and you shouldn't be bothered by it.

 

[Mystik]

But I might use it.

 

[MrHippocrit]

But I might use it.

Then... keep using it.
Harden is a move that only increases the Def stat of the user by x. And because the game sees that it is a normal type move it will give the message that it has no effect on Ghost-types, but it won't make the move useless since it will still increase the stat.