I have a custom claims-based login page which works correctly in Firefox, Chrome, and IE 10. The login page is a standard "choose your login type" scenario that redirects to _windows for Windows logins.
When a user on IE9 or earlier chooses the Windows option and authenticates correctly, they are sent back to the login page. If they click the Windows link they again go back to the login page.
BUT, if we wait some time (don't know how much yet - 1 minute? 2 minutes?) then the Windows link takes them back to the original site. If the user puts the direct site URL in after authenticating, then that also works.
So it appears that the authentication and authorization is working, but that IE9 and earlier are waiting to figure that out somehow. I'm thinking it's a cookie timing issue of some sort but I can't figure out what it is.
What is the best way to solve this?