Oracle Error Message
RMAN-05538: WARNING: implicitly using DB_FILE_NAME_CONVERT
Reason for the Error
The duplicated SPFILE had DB_FILE_NAME_CONVERT set and it has been used to produce datafile names for the new database.
Solution
No action is required. This is an informational message only. If this behavior was not intended, then do not duplicate the server parameter file, or explicitly set DB_FILE_NAME_CONVERT in the DUPLICATE command and retry the operation.