Deadlock on dual when executing a job

Hi,

I am using SQL Developer to create and execute a job. I am using the wizard. But when I apply the wizard, I get an error ORA-4020 "deadlock detected". My operation is very siùple it is "select sysdate from dual". I don't understand why I get a deadlock error because the object is "dual", not a table or so. Below is the output generated by the assistant.

BEGIN
DBMS_SCHEDULER.set_attribute( name => '"SIVOA"."TRUNCATE_EV_48H"', attribute => 'job_action', value => 'begin
select sysdate from dual;
end;');
        DBMS_SCHEDULER.set_attribute_null( name => '"SIVOA"."TRUNCATE_EV_48H"', attribute => 'start_date');
        DBMS_SCHEDULER.set_attribute_null( name => '"SIVOA"."TRUNCATE_EV_48H"', attribute => 'repeat_interval');
DBMS_SCHEDULER.REMOVE_JOB_EMAIL_NOTIFICATION (    
             job_name => '"SIVOA"."TRUNCATE_EV_48H"'
             );
DBMS_SCHEDULER.ADD_JOB_EMAIL_NOTIFICATION (    
             job_name => '"SIVOA"."TRUNCATE_EV_48H"', 
             recipients => 'sombody@somecompany.fr',
             sender => '',
             subject => 'Oracle Scheduler Job Notification - %job_owner%.%job_name%.%job_subname% %event_type%',
             body => 'Job: %job_owner%.%job_name%.%job_subname%
Event: %event_type%
Date: %event_timestamp%
Log id: %log_id%
Job class: %job_class_name%
Run count: %run_count%
Failure count: %failure_count%
Retry count: %retry_count%
Error code: %error_code
%Error message: %error_message%
',
             events => 'JOB_STARTED, JOB_BROKEN, JOB_CHAIN_STALLED, JOB_FAILED, JOB_OVER_MAX_DUR, JOB_SCH_LIM_REACHED',
              filter_condition =>  ''
             );
DBMS_SCHEDULER.enable(name=>'"SIVOA"."TRUNCATE_EV_48H"');
END; 
/

I am using SQL developer version 4.2.0.17.089. And DB is 12.1.

Regards.