A Communiqué instance may still be accessible via dispatcher, though it's answering with 500 status codes.
When multiple renders (ie. Communiqué instances) are used in the dispatcher configuration, the system of penalty points is applied to decide which render to use for the request. When a Communiqué instance returns a 500 code, the dispatcher puts a greater penalty, so that the other renders have a higher priority. However, the faulty instance will still be accessible. Thus it is recommended to monitor the instance logs.