Please note when RAC you need to define scope=both

IE:

Check if there are any hidden "_" parameters.

SQL> SELECT name,description from SYS.V$PARAMETER WHERE name LIKE '\_%' ESCAPE '\';

Remove the hidden parameter, In my case it is "_rac_dbtype_reset"

SQL> alter system reset "_rac_dbtype_reset" scope=both;

Check again

SQL> SELECT name,description from SYS.V$PARAMETER WHERE name LIKE '\_%' ESCAPE '\';

Then STOP and START the DB on ALL NODE in the RAC

SQL> shutdown immediate;

SQL> startup;

Please note when RAC you need to define scope=both

IE:

Check if there are any hidden "_" parameters.

SELECT name,description
FROM SYS.V$PARAMETER 
WHERE name LIKE '\_%' ESCAPE '\';

Remove the hidden parameter, In my case it is "_rac_dbtype_reset"

alter system reset "_rac_dbtype_reset" scope=both;

Check again

SELECT name,description
FROM SYS.V$PARAMETER 
WHERE name LIKE '\_%' ESCAPE '\';

Then STOP and START the DB on ALL NODE in the RAC

shutdown immediate;

startup;