The CLI command 'CC-config session-timeout' was not working in SMG.
By default, the timeout was set at 30 minutes.
Post changing the timeout to any time (whether it is 10 minutes or 40 minutes), the timeout remained at 30 minutes.
This is a known issue.
The fix will be rolled out in next release 10.9.1.
For more information, please contact Broadcom Support.