Rule 701.24d

If an effect would cause a player to shuffle a set of objects into a library, that library is shuffled even if there are no objects in that set. Example: Loaming Shaman says “When this creature enters, target player shuffles any number of target cards from their graveyard into their library.” It enters the battlefield, its ability triggers, and no cards are targeted. When the ability resolves, the targeted player will still have to shuffle their library.

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