RMAN-05169
cannot use a 'format' specifier or a 'to' specifier when connected to a pluggable database and recovery file destination parameter is set
Cause
An attempt to backup data files when connected to a pluggable database (PDB) failed. The format specifier could not be used while the target was set to PDB and the recovery file destination (RFD) parameter was set.
Action
Remove the format specifier and retry the command.