We have seen this issue in rare cases and has exposed itself in reporting. We have machine auth in place for 1000 hours. So once the machine has authenticated it should be cached between SSID A and B. So regardless of where the user roams machine auth is good and all that is left is the user auth.
Its as if there is another secure or security related item that we have overlooked or some issue with a small percentage of clients.
Use cached results is checked on the enforcement tab of the service per rfiler response.
Thanks