Camel message body becomes null when sent to error queue in onException() method.

Issue

I have following camel route:

String destination = "cxf:http://localhost:9090/test?dataFormat=MESSAGE";

    from("jms:queue:dslSource")
        .onException(java.net.ConnectException.class, Exception.class)
            .maximumRedeliveries(3)
            .maximumRedeliveryDelay(3000)
            .retryAttemptedLogLevel(LoggingLevel.INFO)
            .log(LoggingLevel.WARN, "Failed to send message ${body}") // body is not null here
            .log(LoggingLevel.WARN, "Sending message to the error queue: ${body}")   // body is null here
            .to("jms:queue:dslError")
            .end()
        .log(LoggingLevel.INFO, "Sending message ...")
        .setHeader("bridgeDestination", constant(destination))
        .to(destination)
        .log(LoggingLevel.INFO, "received back: ${body}")
        .routeId("example-dsl");

If an exception is thrown, for instance, a ConnectionException due to unavailability of the backend web service, the onException() route will be executed. The first log endpoint:

.log(LoggingLevel.WARN, "Failed to send message ${body}") 

prints out camel exchange IN message body without any problem. However, the second log endpoint:

.log(LoggingLevel.WARN, "Sending message to the error queue: ${body}")

prints out a "Sending message to the error queue: null".

Any reason why the message body becomes a null in this case?