Suppose Alice, Charlie, and Bob are in combat (in that order).
Alice casts Cloud of Daggers centered on Bob. This question explains that Bob takes no damage (yet), as merely creating the area doesn’t trigger the damage.
Charlie casts Thunderwave on Bob, who fails the save. Bob takes 2d8 thunder damage and is pushed 10ft, out of the area created by Cloud of Daggers.
Next is Bob’s turn. Would I be correct to say that Bob never takes damage from the Cloud of Daggers (unless he does something silly like run back into it)?