Camel CSV Component Not Outputting Headers Correctly

I have the following 2.14.1 route:

from("activemq:queue:ABC_FULFILLMENT_REQUEST")
.aggregate(new
ABCFulfillmentCenterAggregationStrategy())
.xpath(
"/o:Order/o:OrderType/o:FulfillmentCenter = '"

com.pluralsight.orderfulfillment.generated.FulfillmentCenter.FULFILLMENT_CENTER_ONE.value()
+ "'", Boolean.class, namespace)
.completionInterval(10000)
.beanRef("aBCFulfillmentProcessor",
"processAggregate").marshal()
.csv().to("file://" +
filePath).to("mock:direct:result");

My aggregation strategy correlates XML where the fulfillmentcenter element's
text is of a certain value. This works correctly. My message translator then
takes the exchange and processes it:

public List<Map;String, Object>> processAggregate(List orders)
throws Exception {
log.info("Processing the aggregate");
List<Map;String, Object>> results = new ArrayList<Map;String,
Object>>();

// 1 - Add the header first
Map<String, Object> header = new HashMap<String, Object>();
header.put("orderNumber", "Order Number");
header.put("firstName", "First Name");
header.put("lastName", "Last Name");
results.add(header);

try {
if (orders != null) {
// 2 - Add each order ID
for (int i = 0; i < orders.size(); i++) {
com.pluralsight.orderfulfillment.generated.Order order =
unmarshallOrder((String) orders
.get(i));
Map<String, Object> row = new HashMap<String, Object>();
row.put("orderNumber",
order.getOrderType().getOrderNumber());
row.put("firstName", order.getOrderType().getFirstName());
row.put("lastname", order.getOrderType().getLastName());
results.add(row);

} catch (Exception e) {
log.error(
"An error occurred while trying to process messages for the
abc fulfillment center: "
+ e.getMessage(), e);
throw e;

return results;

As you can see, I'm accepting the list of orders as the parameter from the
body of the exchange. First, I add a header to the list of maps I plan to
return. I then unmarshal each XML from the input list and build maps to add
to the return list.

Once message processing is complete, I marshall the results into CSV and
then send the contents to a file.

The content that results in the body below is:

Last Name,Order Number,First Name
,1003,Jane,Smith
,1004,Larry,Horse
,1005,Michael,Tester

I expected the header to be in the correct sequence; however, its not. Also,
an extra comma is output to the left. Now, if I don't add the map for the
header, I get the following:

1003,Smith,Jane
1004,Horse,Larry
1005,Tester,Michael

Here are my questions:

1) Is marshalling the csv then sending the exchange to a file an accepted
approach? Or should I be using some other component in between the csv and
file components.
2) How do I maintain the order of elements in a row. For instance, I want to
make sure that the columns are order number, first name, last name; however,
the map keys are not the way I would want to assure order. Any guidance
would be appreciated.

Let me know if there is anything else I can provide. Thank you in advance
for your help.