How come the Ralts that I caught has Confuse Ray?

Question

Caught Ralts through Dexnav and it had Confuse Ray. Can someone explain why?

Comments

I think the Dexnav lets you catch things with egg moves.

Answer 1

Hidden Pokémon can have their normal first move replaced with a special move, randomly selected from the Egg Moves of the first Pokémon in its evolutionary family.

Source