BUG #3417: Foreign key constraint violation occurs unexpectedly

The following bug has been logged online:

Bug reference:      3417
Logged by:          David Boesch
Email address:      davidboesch@datasc.com.au
PostgreSQL version: 8.2.4
Operating system:   Linux Redhat Linux linux2 2.4.20-8 #1 Thu Mar 13
17:54:28 EST 2003 i686 i686 i386 GNU/Linux
Description:        Foreign key constraint violation occurs unexpectedly
Details:

I have created a table with a surrogate primary key like so.

create table reference(
        id              serial primary key,
        name            varchar(50) not null,
        description     varchar(50)
);

Then I create a table which references the primary key like so.

create table a(col1 integer references reference(id));

I add data to reference

select * from reference shows as

 id |      name      |          description
----+----------------+--------------------------------
 11 | rd             | road
 12 | st             | street
 13 | way            | way
 14 | close          | close
 15 | bend           | bend
  3 | vic            | victoria
  4 | nsw            | new south wales
  5 | qld            | queensland
  6 | nt             | northern territory
  7 | sa             | south australia
  8 | tas            | tasmania
  9 | wa             | western australia
 10 | act            | australian captial territory
 16 | nab            | national australia bank
 17 | cba            | commonwealth bank of australia
 18 | anz            | bank of new zealand
 19 | westpac        | westpack banking corporation
 20 | bqld           | bank of queensland
 21 | mqb            | macquarie bank
 22 | suncorp        | suncorp
  1 | unit           | unit
  2 | lot            | lot
 23 | assets         | assets
 24 | liabilities    | liabilities
 25 | equity         | equity
 26 | income         | income
 27 | cost of sales  | cost of sales
 28 | expenses       | expenses
 29 | other income   | other income
 30 | other expenses | other expenses
 31 | au             | australia
 32 | usa            | United States of America
 33 | oakleigh       | oakleigh
 34 | st albans      | st albans


When inserting into a with the following

dsc=# insert into a (col1) values(7);
ERROR:  insert or update on table "a" violates foreign key constraint
"a_col1_fkey"
DETAIL:  Key (col1)=(7) is not present in table "reference".
STATEMENT:  insert into a (col1) values(7);
ERROR:  insert or update on table "a" violates foreign key constraint
"a_col1_fkey"
DETAIL:  Key (col1)=(7) is not present in table "reference".


Why do I get a foreign key constraint violation when I have the id of 7 in
the table?

I must be missing something here.