TransactionCreateRequest doesn't connect with order, InstantTransactionCreateRequest does

[loki42]

This code worked:

    transaction = s.transactions.create(
        components.InstantTransactionCreateRequest(
            shipment=shipment,
            carrier_account=fedex,
            servicelevel_token="fedex_international_priority",
            order=current_order.object_id
        )
    )

and the order is associated correctly. However this code

    transaction = s.transactions.create(request=components.TransactionCreateRequest(
        async_=False,
        label_file_type=components.LabelFileTypeEnum.ZPLII,
        metadata=str(current_order.order_number),
        rate=selected_rate,
        order=current_order.object_id
    ))

Does not. The label is generated but the order isn't marked as fulfilled and doesn't have the transaction associated with it.