BUG #4516: FOUND variable does not work after RETURN QUERY

The following bug has been logged online:

Bug reference: 4516
Logged by: Michal szymanski
Email address: szymanskim(at)datera(dot)pl
PostgreSQL version: 8.3
Operating system: Windows
Description: FOUND variable does not work after RETURN QUERY
Details:

This short program display two rows instead one. If I use RETURN NEXT it
works.

CREATE TABLE test_table (
value VARCHAR
);
INSERT INTO test_table VALUES ('a');
INSERT INTO test_table VALUES ('b');

CREATE OR REPLACE FUNCTION test()
RETURNS SETOF test_table AS
$BODY$
DECLARE
BEGIN

RETURN QUERY
SELECT * FROM test_table WHERE value='a';
IF NOT FOUND THEN
RETURN QUERY
SELECT * FROM test_table WHERE value='b';
END IF;

RETURN;
END;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;

select * from test()