BUG #5434: select from xpath_table gives wrong results

The following bug has been logged online:

Bug reference: 5434
Logged by: Oleg
Email address: sacramento_fan(at)mail(dot)ru
PostgreSQL version: 8.4.3
Operating system: KUbuntu
Description: select from xpath_table gives wrong results
Details:

Here is a code:

create table tmp_xml(rowId SERIAL UNIQUE NOT NULL,
xml_context xml,
CONSTRAINT PK_tmp_xml PRIMARY KEY (rowId));

insert into tmp_xml (xml_context)
values('<root>'
'<obj obj_id="1" obj_name="First Object"/>'
'<obj obj_id="2" obj_name="Second Object" obj_master="1"/>'
'<obj obj_id="3" obj_name="Third Object"/>'
'<obj obj_id="4" obj_name="Fourth Object" obj_master="1"/>'
'</root>');

SELECT t.OBJ_ID, t.OBJ_NAME, t.OBJ_MASTER
FROM xpath_table('rowId',
'xml_context',
'tmp_xml',

'/root/obj/@obj_id|/root/obj/@obj_name|/root/obj/@obj_master|',
'true')
AS t(row_id integer,
OBJ_ID integer,
OBJ_NAME varchar(255),
OBJ_MASTER INT
);

I was sure, that result of this query should be like this:

obj_id | obj_name | obj_master
----------------------------------------
1 | First Object |
2 | Second Object | 1
3 | Third Object |
4 | Fourth Object | 1

But instead of I got this result:

obj_id | obj_name | obj_master
----------------------------------------
1 | First Object | 1
2 | Second Object | 1
3 | Third Object |
4 | Fourth Object |

Why is this so? Maybe I use xpath_table wrong way?