Exchange OWA 2013 SSO

Makes sense that that would happen. OWA 2013 redirects you to the /owa/auth/logon.aspx page, which is also the URI that causes the form to be detected, thus causing your stored login credentials to be resubmitted.

You might try experimenting with the form detection settings in the SSO configuration. Checking for a header/value or cookie/value pair that only exists in the initial server response, and not in the post-logoff redirect response, for example.

You can also trigger the form detection based on a URI/header/cookie that doesn't exist, using the Request Negative option: http://support.f5.com/kb/en-us/products/big-ip_apm/manuals/product/apm-sso-config-11-2-0/3.html