Posting on behalf of a customer.
To complete the SAML experience for an NXT org it is desired to take advantage of the Sign Out URL below:
Ideally once the Sign Out URL is populated and a user signs out of NXT, user should be redirected to that Sign Out Url (Most common target landing page would be the user’s SAML enabled apps landing page).
Currently on log out, although the Sign Out URL is populated, user would get redirected to the NXT login page instead. This post to to help get support/honoring of the Sign Out URL.