In a centralized agent configuration untick "Notifications" and restart IIS. (com.sun.identity.config.notifications.enable=false)
Then access a protected resource and authenticate.
then go to <openam url>/UI/Logout
Wait a minute then try and access the protected url again.
As session notifications are off. In the debug log (or access logs) there should be no http post coming from AM. The session should still remain valid and the protected resource page should be redisplayed
Post is received and session invalidated.
The protected resource is redirected to Authentication.
Only by setting com.sun.identity.config.notifications.enable=false in the agent.conf