Keycloak Logout is not working with Owin.Security.Keycloak

Question

I'm integrating keycloak to a .net framework 4.7.2 MVC project.

My Startup class is like this;

public class Startup
{
    const string persistentAuthType = "keycloak_auth"; 
    private string keycloakBaseUrl = ConfigurationManager.AppSettings["KeycloakBaseUrl"];
    private string keycloakRealm = ConfigurationManager.AppSettings["KeycloakRealm"];
    private string keycloakClient = ConfigurationManager.AppSettings["KeycloakClient"];
    public void Configuration(IAppBuilder app)
    {
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

        app.UseCookieAuthentication(new CookieAuthenticationOptions
        {
            AuthenticationType = persistentAuthType
        });

        app.SetDefaultSignInAsAuthenticationType(persistentAuthType);

        app.UseKeycloakAuthentication(new KeycloakAuthenticationOptions
        {
            Realm = keycloakRealm,
            ClientId = keycloakClient,
            KeycloakUrl = keycloakBaseUrl,
            AuthenticationType = persistentAuthType,
            AllowUnsignedTokens = false,
            DisableIssuerSigningKeyValidation = true,
            DisableIssuerValidation = true,
            DisableAudienceValidation = true,
            DisableRefreshTokenSignatureValidation = true,
            TokenClockSkew = TimeSpan.FromSeconds(2)
        });

    }
}

For the logout, I tried two options:

[Authorize]
public ActionResult KeycloakLogout()
{
    var id_token = GetIDToken();
    string keycloakLogoutUrl = String.Format("{0}/realms/{1}/protocol/openid-connect/logout?id_token_hint={2}", keycloakBaseUrl, keycloakRealm, id_token);
    return Redirect(keycloakLogoutUrl);
}

Above example, I see the keycloak page saying I am logged out. However User.Identity.IsAuthenticated is still true.

Then I tried:

[Authorize]
public ActionResult KeycloakLogout()
{
 HttpContext.GetOwinContext().Authentication.SignOut("keycloak_auth");
return Redirect("homeurl");
}

In this case, keycloak shows an error "Missing Parameters: id_token_hit". However in this case User.Identity.IsAuthenticated is false.

How to perform the logout correctly?