We've been using DUO 2FA for about a year now, no problems.

The DUO Prompt appears on the left pane of the log in page - where the username & password textboxes are, and the website stays at the same URL (i.e. pmp.<FQDN>). The whole site has a certificate that is associated to to pmp.<FQDN>.

After updating to v11104 the DUO prompt redirects the entire page to a DUO prompt page - the DUO prompt is sent to my mobile device - it then redirects back to URL: <servername>/ and not only does the login fail, the certificate comes up as invalid as the FQDN has been dropped from the URL.
Trying to log in again, it works a second time - the URL is once again redirected to a DUO page - the DUO prompt comes to my mobile device, and PMP logs in, but the URL is still wrong, and missing the FQDN which causes the site certificate to be invalid.

Any ideas?