In Master Fu's box, the peacock miraculous is missing.
My theory is that Adrien's mom is in possession of the peacock miraculous, this could be the reason why she disappeared. It could be possible that she was in possession of the peacock and the butterfly but left the butterfly miraculous behind when she disappeared. Gabriel Agreste could have found the butterfly miraculous after his wife's disappearance. After his wife disappeared, Gabriel Agreste was left a changed man (check the wiki I'm not making this up), the reason he wants the ladybug and chat noir miraculous could be because he's trying to find his wife. Or it's possible she's dead and he wants to use the power to bring her back.
Another theory could be that Gabriel Agreste found out his wife was in possession of the peacock miraculous, because he found out she could have run away and still Gabriel finds the butterfly miraculous and wants to use the ladybug and chat noir to bring her back/find her.
As more episodes come out I'll try to build on these theories, EVERYTHING IS GETTING SO INTENSE!!!