Incorrect expired datafile copy

Oracle 12cR2. When I was moving a datafile from my +FRA diskgroup to +DATA (per Doc 330103.1), I accidentally typed

copy datafile '+FRA/...' to '+DATA';

twice. But I went ahead and switched datafile anyway. The database is up and running fine. Now I want to delete the unused copy:

In SQL*Plus:

SQL> select file_name from dba_data_files where tablespace_name = 'UNDOTBS1';

FILE_NAME

-----------------------------------------------------------------------------

+DATA/DBCD12/4FE21630ABB821EEE05314E5460AE6C8/DATAFILE/undotbs1.265.944738555 <-- this file, the only one in UNDOTBS1, is being used

In ASMCMD:

ASMCMD [+data/DBCD12/4FE21630ABB821EEE05314E5460AE6C8/datafile] > ls -l