Expdp fails with ORA-31626, ORA-31633, ORA-00955

Full database backup using expdp was failing with following error.
I have checked with the following command.

expdp userid=\'/ as sysdba\' directory=bk_dir full=y job_name=dfull_backup dumpfile=test.dmp logfile=testlog

ORA-31626: job does not exist
ORA-31633: unable to create master table "SYS.DFULL_BACKUP"
ORA-06512: at "SYS.DBMS_SYS_ERROR", line 95
ORA-06512: at "SYS.KUPV$FT", line 863
ORA-00955: name is already used by an existing object


Issue:
select * from DBA_DATAPUMP_JOBS;
showing there have a job name DFULL_BACKUP which status is not running.
select table_name from dba_tables where table_name='DFULL_BACKUP';
shows the master table created under SYS schema.

Resolution:

Connect as sysdba.

SYS@shamim AS SYSDBA>drop table DFULL_BACKUP;

Table dropped.

Now we can run the expdp again without error.