ORA-08104: this index object 75350 is being online built or rebuilt

SQL> alter index S.SYS_C007740 rebuild online tablespace s_data01;
alter index S.SYS_C007740 rebuild online tablespace s_data01
*
ERROR at line 1:
ORA-08104: this index object 75350 is being online built or rebuilt

SQL> conn / as sysdba
Connected.
SQL> select obj#,flags from ind$ where obj#=75350;

OBJ# FLAGS
---------- ----------
75350 2563

declare

isclean boolean;

begin

isclean :=false;

while isclean=false

loop

isclean := DBMS_REPAIR.ONLINE_INDEX_CLEAN(dbms_repair.all_index_id,dbms_repair.lock_wait);

dbms_lock.sleep(10);

end loop;

end;

/

PL/SQL procedure successfully completed.

SQL> select obj#,flags from ind$ where obj#=75350;

OBJ# FLAGS
---------- ----------
75350 2051

SQL> alter index S.SYS_C007740 rebuild online tablespace s_data01;

Index altered.