1) does not prove we are not spec compliant. The reply to the temp queue could have been compleated before the message as delivered to the client. Therefore the echo service does not get an error message. The message disappears because it is sitting in a temporary queue, and the client connection has terminated. The temporary queue disappears.
2) Sound right, submit a bug report to sf.net/projects/jboss so that we don't forget to fix this.