After CAS got UR6, I found something strange, if you try to login to OWA for the first time after the UR6 applied to CAS, users will get
"Your session has timed out. To Protect your account from unauthorized access, Outlook Web Access automatically closed its connection to your mailbox after a period of inactivity. Please re-enter your name and password"
If users re-enter username and password, OWA opens up and let the user in. If you logout and try to log back in it does not show the same behavior, you can close the IE and you can log back in without any problem, however if you reboot your PC and try to login again you will get the "Your session has timed out." notice and you will have to re-enter your user name and password.