Pl identify exact OS version. Pl post the commands used to create the dump files listed.
userid="/ as sysdba"
This should not be used - pl see first Note section at Data Pump Import
ORA-39140: dump file "/oraacfs/acfsmounts/acfs01_t2_acfs_vol01/Q799175/exp_rest.dmp" belongs to job "BISADMIN"."SYS_EXPORT_SCHEMA_02"
See MOS Doc 289445.1
Essentially the problem is 'file already exists'......