When the application is deleted in System/Porta and notified to Zync, Zync makes a show request and finds 404 because it does not exist anymore, so it builds an application containing just nil, without data and without the client_id
https://github.com/3scale/zync/blob/90c81e21ec2024e5de9acd4b5035c2f6682376f3/app/services/fetch_service.rb#L55-L79
Then the KeycloakService does nothing at all because the client_id is not present
https://github.com/3scale/zync/blob/90c81e21ec2024e5de9acd4b5035c2f6682376f3/app/services/integration/keycloak_service.rb#L47