PostLogoutUri is always null

[apetrut]

I have an Angular app that is redirecting to the STS login page for login. Once the login is finished it redirects back to the FE app.
When the user logs out with success from FE, he is redirected to the Duende logout page that doesn't contain the "here" button because the PostLogoutUri is null.

If the user tries to log back again, after login he is redirected to the Duende Identity Server page instead of the FE app landing page because it has no redirect url in query string.

For the login flow the redirect url appears in the query string, but for the logout flow it's not. PostLogoutRedirectUri is always null.