Access Manager 4.2 Access Gateway installed and protecting Web Applications. Users can successfully view the applications after successfully authenticating against the Identity (IDP) Server. One particular Application was protected with the 'Any' contract as opposed to a specific contract - when users accessed the application and were redirected to the IDP server, these users could see all available contracts displayed but could not access any of them. The issue seemed to be specific to IE 11, as Firefox and Chrome did not show the same issue.
Disable compatibility mode in IE - turns out it was enabled by default. This can be done by changing the IE expert options (http://www.howtogeek.com/128289/how-to-disable-compatibility-mode-in-internet-explorer/).
Another option that is to include the following meta tag in the IDP login page - this removes the requirement to make changes at the browser level
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
Applying this in the browser overwrites the compatibility Setting for that browser.