Adventure text currently say "You may cast this card as an Adventure, after you do exile it." This implies that as long as the card is cast it will exile which is incorrect. The actual rules for adventure state "715.3d Instead of putting a spell that was cast as an Adventure into its owner’s graveyard as it resolves, its controller exiles it. For as long as that card remains exiled, that player may cast it. It can’t be cast as an Adventure this way, although other effects that allow a player to cast it may allow a player to cast it as an Adventure." I think the Adventure text should read something more like "You may cast this card as an Adventure, after it resolves exile it." to clarify the actual interaction when the spell is countered or fizzles.