If the times (System and Database) do not match, often schedules can kick off at the incorrect time. So, if your database time is showing an hour or two off the schedules may also kick off at that time.
Usually this is something that was accidentally updated be it on the database, server, or in our application. Under older versions of java DST could also cause this.
You can use the following to ferret out where the time is actually off:
SQL> select dbtimezone from dual;
SQL>select SYSTIMESTAMP from dual;
SQL>select * from aw_master_config where item='MASTER_TIMEZONE';
On Unix/Linux you can also check the server time using:
If times are off your admins will need to sync them up.