Postgres storing time in strange manner

I don't have a clue why it's doing this - has anyone else seen this sort of
behavior, or know why it might be doing it?  It shows times wrong, for
instance, it shows 00:04:60 where it should show 00:05:00.  See below:

gabrielle=# select * from scheduled_query_groups;
 group_id | group_name | group_type_id | interval |   run_at    |
last_run        | exec_upon_completion
----------+------------+---------------+----------+-------------+------------
------------+---------------------- 2 | test       |             1 | 00:04:60

 | 00:00:00-05 | 0001-01-01 04:59:60.00 |

(1 row)

gabrielle=# \d scheduled_query_groups;
                                       Table "scheduled_query_groups"
        Column        |           Type           |
Modifiers
----------------------+--------------------------+---------------------------
------------------------------- group_id             | integer

   | not null default

nextval('sq_groups_group_id_seq'::text)
 group_name           | character varying(32)    | not null
 group_type_id        | integer                  | not null
 interval             | interval                 | not null default '5
minutes'
 run_at               | time with time zone      | not null default '00:00:00
EST'
 last_run             | timestamp with time zone | not null default
'0001-01-01 00:00:00 EST'
 exec_upon_completion | character varying(128)   |
Primary key: scheduled_query_groups_pkey
Unique keys: scheduled_query__group_name_key
Triggers: RI_ConstraintTrigger_16607

--
Casey Allen Shobe / Network Security Analyst & PHP Developer
SecureWorks, Inc. / 404.327.6339 x169 / Fax: 404.728.0144
cshobe@secureworks.net / http://www.secureworks.net
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