ORA-65500 When using DUPLICATE to Create Standby Database

Oracle Database - Enterprise Edition - Version 12.2.0.1 + RU 12.2.0.1.171017
Operation System - Oracle Solaris 11.3 SPARC

When running RMAN command DUPLICATE to create physical standby database as following:

RMAN> duplicate target database 
2>    for standby 
3>    from active database 
4>    dorecover 
5>    spfile 
6>      reset control_files 
7>      set db_unique_name='DBNEW' 
8>      set fal_server='DB01' 
9>    nofilenamecheck; 

using target database control file instead of recovery catalog

Starting Duplicate Db at 15-JAN-18
current log archived
... ...

Got error ORA-65500:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 01/15/2018 11:46:19
RMAN-05501: aborting duplication of target database
RMAN-03015: error occurred in stored script Memory Script
RMAN-03009: failure of sql command on clone_default channel at 01/15/2018 11:46:19
RMAN-11003: failure during parse/execution of SQL statement: alter system set  db_unique_name='DBNEW' comment='' scope=spfile
ORA-32017: failure in updating SPFILE
ORA-65500: could not modify DB_UNIQUE_NAME, resource exists

Oracle reported this issue as Bug 20977794 which causes the ORA-65500 to be returned with any attempt to change DB_UNIQUE_NAME for database when a CRS resource for it exists. As RMAN attempts to make a change to db_unique_name, this error will occur.

Current system is configured with Oracle Restart (Grid Infrastructure - standalone) 12.2.0.1. Although it is supposed to be fixed in 12.2.0.1 base release, the error still happened. Anyway, we can safely try to remove database resource from crs registry as workaround,

[oracle@dbaplus]$ srvctl config database
DBNEW

The database DBNEW does exist in the crs registry, try to remove it

[oracle@dbaplus]$ srlvctl remove database -db DBNEW
Remove the database DBNEW? (y/[n]) y
[oracle@dbaplus]$

Then DUPLICATE can run successfully.