I see we're currently arguing over the placement of typing and a certain inconsistency that seems to have not fallen in my range of [desired] attention.
Primary Type/Secondary Type
Noivern's primary type is Flying. Its secondary type is Dragon. I see no problem with that.
Consistency is not a problem here. You guys seem to be debating the problem of the placement of types and how it is unconventional. In the end, the placement of types does not seem to affect STABs. It's just a way of giving a Pokémon a type logically.