ALTER SYSTEM REGISTER each 60 seconds on Oracle Restart 12c

Hi everyone.

I have a issue. I have two Oracle systems 12c, the first is a RAC, and the other is a Oracle Restart.

I have enabled mixed auditing, and I can detect in table the event "ALTER SYSTEM" with sql text "ALTER SYSTEM REGISTER" each 60 seconds occurs in Oracle Restart System.

It doesn't occurs in RAC System (only in startup)

I have checked the Oracle Restart local listener parameter and the value is the IP hostname and default port  

SQL> show parameter local

NAME                 TYPE    VALUE

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

local_listener            string    (ADDRESS=(PROTOCOL=TCP)(HOST=

                         Oraclesrv)(PORT=1521))

select os_username, userhost, action_name, event_timestamp from unified_audit_trail where event_timestamp>sysdate-1 AND ACTION_NAME='ALTER SYSTEM' order by event_timestamp desc;