IIS Web App Redirects Client to Port 80 from 443

You now need to define what that redirect actually looks like. The Redirect Rewrite option, applied to an HTTPS VIP, is intended to rewrite http:// redirect Location headers to https://. If, however, the redirect is not a 30x-type message, then this method won't catch it. If possible, spin up a client side capture utility like Fiddler or HTTPWatch and watch how the client interacts with the site, and what the server sends to generate the redirect to the port 80 URL.