Using ADFS iApp, have to sign in twice to ADFS

Using a Viprion guest running 11.6.1 with APM. I used iApp to configure the F5 to replace the proxy server. Authentication is happening, but after logging into the F5 successfully the next page displayed is the login page for ADFS instead of being logged into ADFS. If the request ID is removed from the URI then the user is logged into ADFS without re-entering their credentials.

 

If we disable Forms SSO in the iApp setup then the user must enter credentials twice.

 

We setup according to "Securing ADFS with the Big-IP APM" in the deployment guide ( https://www.f5.com/pdf/deployment-guides/microsoft-adfs-dg.pdf )