Consider this sequence on a 3-node set. Why can the value written by client X be lost even though the write returned successfully to X?

// 3-node set, client X (no explicit write concern) db.orders.insertOne({ _id: 1, status: "paid" }); // ack returned to X // ... primary is network-partitioned from the other two // ... a new primary is elected among the remaining majority // ... old primary rejoins