After a forced stop job in dbms_sheduler session some time remains active, although the job has been stopped. How do you know that the session is closed, do not use v$session views.
I stop all jbos as
FOR r IN (SELECT JOB_CLASS FROM JBSD$SCHEDULER_JOBS) LOOP
dbms_scheduler.disable(name => 'SYS.'||r.JOB_CLASS, force => TRUE);
dbms_scheduler.stop_job(job_name => 'SYS.'||r.JOB_CLASS, force => TRUE);
END LOOP;
and throws an exception in function run the job to interrupt her