We are using Sustainsys.Saml2 SSO framework with Sitecore Identity Service and external client SSO configuration. Our problem is when a login user logout of application, we have a successful logout at Sitecore Identity server but the client is not notified the user has logged out.
If the same users select to back in, the SSO call immediate return the user credentials and claims without requiring the user to login with their credentials.
The potential issue is someone else using the same machine, they will be login as the previous user.
I have read Sustainsys.Saml2 and Sitecore SSO SingleSignout documentation but have not been able to resolve this issue.
Only errors I see after logout are
https://*****/sitecore/shell/FrontChannelLogout?sid=b0bff05661f61351aca6424ae90fc59d&iss=https%3A%2F%2F*****.net 400 Bad Request
https://*********/sitecore/shell/FrontChannelLogout?sid=27b7f3ef8a747a41e0bdc6114a3a4f5d&iss=https%3A%2F%2F*****.net 404
