Strange constraint violation when applying rules to a view.

Hello.

This section works fine:

CREATE TABLE torder (
        id      INT8 NOT NULL PRIMARY KEY
);

CREATE TABLE torder_row (
        id        INT8 NOT NULL PRIMARY KEY,
        torder_id INT8 NOT NULL REFERENCES torder (id) ON DELETE RESTRICT
);

CREATE VIEW vorder(orderID, rowID) AS SELECT 1, 1 FROM torder;

CREATE RULE vorder_ins AS ON INSERT TO vorder
  DO INSTEAD
  (INSERT INTO torder VALUES (NEW.orderID);
   INSERT INTO torder_row VALUES (NEW.rowID, NEW.orderID);
   );

CREATE RULE vorder_upd AS ON UPDATE TO vorder
  DO INSTEAD
  (INSERT INTO torder (id) VALUES (NEW.orderID);
   UPDATE torder_row SET torder_id = NEW.orderID;
   DELETE FROM torder WHERE id = OLD.orderID;
   );

INSERT INTO vorder VALUES (1, 1);
UPDATE vorder SET orderID = 2;
SELECT * FROM vorder;


But when I change the view to the following:

CREATE VIEW vorder(orderID, rowID) AS SELECT 1, 1 FROM torder;
becomes
CREATE VIEW vorder(orderID, rowID) AS SELECT id, 1 FROM torder;

I get the following error:
ERROR:  insert or update on table "torder_row" violates foreign key
constraint "$1"

This was just a small test so the table definitions and view makes
little sense, but generally, any time the view actualy selects columns
it seems the update rule fails with a constraint violation even though
it shouldn't.

Thank's for reading!
/Peter