casting interval to time

Hi
psql -V
psql (PostgreSQL) 7.3
SELECT cast(cast('1 day 12 hours' as interval) as time);   time
---------- 12:00:00
(1 row)


psql -V
psql (PostgreSQL) 7.3.2
SELECT cast(cast('1 day 12 hours' as interval) as time);  time
---------- 00:00:00
(1 row)


Did I miss something? I looked into 'history' file, but I couldn't find 
anything interesting about changes in casting interval into time.

I found replacement for this problem, but I wan't just to know what 
happened:
('1970-1-1'::date+some_interval)::time

Regards,
Tomasz Myrta