strange behaviour of gettimeofday() and pg_dump

OK, once more post about the subject, because after some investigation
it looks like a real and serious postgres bug. (7.1.3)

table definition with one (from many) columns:

 timestamp       | timestamp with time zone | not null default timeofday()

and the query:
db=# select timestamp,extract( seconds from timestamp) from history where id=274259;
                  timestamp         | date_part
         ---------------------------+-----------
          2001-09-22 20:07:60.00+02 | 59.998003
          (1 row)

as You can see, first alement shows 60.00 which is WRONG!
at first sight i thought its average, but its not -> 60.00 !!! (two zeroes after decimal period)

it causes failures at pg_dump and shows that postgres has broken timestamp type.

or maybe i don't understand sth ?

--
radoslaw.stachowiak.........................................http://alter.pl/