Issue Summary

Admins for SSO-enabled audience-specific pages are redirected to the /access/login form when clicking "View status page" inside manage.statuspage.io. 

This appears to be related to how /access/login is deciding whether to 302 redirect to the IdP. We were able to toggle this behavior by adding or removing the _spsess cookie in the request. 

curl --cookie '_spsess=<session_cookie>' https://jessetestaudiencespecificpage.statuspage.io/access/login -v
< HTTP/2 200

without:

curl 'https://audiencespecificpage6.statuspage.io/access/login' -v
< HTTP/2 302
< location: <IdP redirect>

Steps to Reproduce

1. Have an audience-specific page setup with SSO enabled.
2. Login to manage.statuspage.io and go to that audience-specific page in manage.
3. Click view status page.

Expected Results

You are redirected to the page's IdP:

1. https://audiencepage.statuspage.io/ -> 302 redirect to
2. https://audiencepage.statuspage.io/access/login -> 302 redirect to 
3. https://my.IdP

Actual Results

You are taken to the page-viewer login form and asked for username/password:

1. https://audiencepage.statuspage.io/ -> 302 redirect to
2. https://audiencepage.statuspage.io/access/login -> 200

Workaround

Access the audience-specific page in an incognito window or without an active session in manage.statuspage.io.