User Logout request deny???

You will get much, much more information to the session report and will see how the APM flow goes in detail and where it may go wrong. Also you will see all the session variables.

Other impact will be quite a bit more logging into the /var/log/apm -log file as everything APM related will also go there. Depends how much APM related traffic there is. How much traffic/users you have? Anyway for troubleshooting you need more info.. You can and should always turn the debug back to normal after resolving the issue.