org.eclipse.jetty.io.EofException seen in the Fuse logs under load

Issue

I'm experimenting with different routes from fuse to external services using SOAP. Things go fine if I run the tests manually, one at a time.
When I run concurrent load, I get the exceptions - on both Fabric Containers running the same profile.

Stack Trace:

org.eclipse.jetty.io.EofException
  at org.eclipse.jetty.http.HttpGenerator.flushBuffer(HttpGenerator.java:914)
  at org.eclipse.jetty.server.AbstractHttpConnection.flushResponse(AbstractHttpConnection.java:686)
  at org.eclipse.jetty.server.AbstractHttpConnection$Output.close(AbstractHttpConnection.java:1108)
  at org.apache.camel.util.IOHelper.close(IOHelper.java:326)
  ...