Not sure what causes this problem, but when I run the request
select to_char(sysdate, 'HH24:MM') from dual;
I always get the same time 15:08. I even test another Oracle DBMS on another machine (also Windows) and got the same result.
HH24: MM gives you the hours (HH) in 24-hour format and the month (August 08).
You should probably have entered HH24: MI ...;)
MM is the code of the month. You want MI in a minute.
MM
MI