I was playing Mage and had an active Mirror Entity " Secret: After your opponent plays a minion, summon a copy of it."
My Opponent played an Archdruid Naralex " Dormant: for 2 turns. While Dormant, add a Dream card to your hand at the end of your turn." and I got a copy.
At that point, there was nothing but two dormant Archdruid Naralex in play.
When my opponent ended their turn, the dormant Archdruids both gave my opponent a dream card using the generate effect.
This happened again the following turn while they were still dormant.
I don’t know if this is a bug or a gross misunderstanding of the text, but the Hearthstone Wiki describing the cards and all of their effects, particularly generate and summon, did not reveal why my opponent got both cards.
I took a single screenshot. https://ibb.co/Zhrm9Yq