UpdateOne function not working properly

[Trojan9]

final selector = {
"path": 'services/${item.serviceId}'
};
final modifier = UpdateOperator.set({'bookOrderId': item.bookOrderId, 'name': item.name});
await CollectionMongo.salons.updateOne(filter: selector, update: modifier);

  only the last item("name") in the modifier gets updated on mongo, leaving out 'bookOrderId' . testing from IOS simulator