Insufficient privileges to shutdown CDB with common user in 12c

I have a common user in the database with SYSDBA privilege and I am not able to shutdown the database with it.

I get insufficient privileges.

sys@cdbtest>grant sysdba to C##TEST container=all;

Grant succeeded.

sys@cdbtest>select * from v$pwfile_users where username='C##TEST';

USERNAME       SYSDB SYSOP SYSAS SYSBA SYSDG SYSKM     CON_ID

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

C##TEST       TRUE  TRUE  FALSE FALSE FALSE FALSE    0

c##test@cdbtest>show user

USER is "C##TEST"

c##test@cdbtest>shut immediate;

ORA-01031: insufficient privileges

Is there anything I am missing here?