My opponent controlled only lands, the new Elenda, and an Ancestor Dragon. I tutored for Emrakul but was unable to cast it despite having more than enough mana. I also could not cast Lumra from the command zone. The cards weren't even highlighted. It WOULD let me cast the Birds of Paradise in my hand, though. No effects or spells were played that would prevent me from casting my cards, e.g. no Single Combat, Silence, or anything like that. I assume this is a bug associated with either or both of the FDN cards in this game. Attached is a screenshot and my game log.