Lier, Disciple of the Drowned can't flashback adventures

[[Lier, Disciple of the Drowned]]'s second ability should allow its controller to cast the adventure side of a card in their graveyard by paying the flashback cost offered by Lier. As it stands, with an adventure in your graveyard, Xmage does not allow you to attempt to cast the card. See [this video](https://youtu.be/8bu3TNaz6q8) for specifics on why this unintuitive interaction is allowed.