2021-04-16 : Dazzling Sphinx’s triggered ability lets you cast the exiled card during the resolution of the ability. It doesn’t allow you to wait and cast the card later.

2021-04-16 : If the exiled instant or sorcery card has an {X} in its mana cost, you must choose 0 as the value of {X}.

2021-04-16 : You may choose not to cast the instant or sorcery card that you exiled. In that case, it will be put on the bottom of the library with the rest of the exiled cards.