nightwatch.js log output when attempt to close a (chromedriver|firefox selenium grid) session with attribute #data set to empty string

nightwatch-delete-request-error.log

INFO Request: DELETE /wd/hub/session/fa148a22-198f-4216-b91b-7b02c645a03c 
 - data:   
 - headers:  {}
There was an error while executing the Selenium command
cannot forward the request null
ERROR Response 500 DELETE /wd/hub/session/fa148a22-198f-4216-b91b-7b02c645a03c{ status: 13,
  sessionId: 'fa148a22-198f-4216-b91b-7b02c645a03c',
  value: 
   { class: 'org.openqa.grid.common.exception.GridException',
     stackTrace: 
      [ { fileName: 'RequestHandler.java',
          lineNumber: 136,
          className: 'org.openqa.grid.web.servlet.handler.RequestHandler',
          methodName: 'process' },
        { fileName: 'DriverServlet.java',
          lineNumber: 84,
          className: 'org.openqa.grid.web.servlet.DriverServlet',
          methodName: 'process' },
        { fileName: 'DriverServlet.java',
          lineNumber: 74,
          className: 'org.openqa.grid.web.servlet.DriverServlet',
          methodName: 'doDelete' },
        { fileName: 'HttpServlet.java',
          lineNumber: 733,
          className: 'javax.servlet.http.HttpServlet',
          methodName: 'service' },
        { fileName: 'HttpServlet.java',
          lineNumber: 820,
          className: 'javax.servlet.http.HttpServlet',
          methodName: 'service' },
        { fileName: 'ServletHolder.java',
          lineNumber: 565,
          className: 'org.seleniumhq.jetty7.servlet.ServletHolder',
          methodName: 'handle' },
        { fileName: 'ServletHandler.java',
          lineNumber: 479,
          className: 'org.seleniumhq.jetty7.servlet.ServletHandler',
          methodName: 'doHandle' },
        { fileName: 'SessionHandler.java',
          lineNumber: 225,
          className: 'org.seleniumhq.jetty7.server.session.SessionHandler',
          methodName: 'doHandle' },
        { fileName: 'ContextHandler.java',
          lineNumber: 1031,
          className: 'org.seleniumhq.jetty7.server.handler.ContextHand
          methodName: 'doHandle' },
        { fileName: 'ServletHandler.java',
          lineNumber: 406,
          className: 'org.seleniumhq.jetty7.servlet.ServletHandler',
          methodName: 'doScope' },
        { fileName: 'SessionHandler.java',
          lineNumber: 186,
          className: 'org.seleniumhq.jetty7.server.session.SessionHandler',
          methodName: 'doScope' },
        { fileName: 'ContextHandler.java',
          lineNumber: 965,
          className: 'org.seleniumhq.jetty7.server.handler.ContextHandler',
          methodName: 'doScope' },
        { fileName: 'ScopedHandler.java',
          lineNumber: 117,
          className: 'org.seleniumhq.jetty7.server.handler.ScopedHandler',
          methodName: 'handle' },
        { fileName: 'HandlerWrapper.java',
          lineNumber: 111,
          className: 'org.seleniumhq.jetty7.server.handler.HandlerWrapper',
          methodName: 'handle' },
        { fileName: 'Server.java',
          lineNumber: 349,
          className: 'org.seleniumhq.jetty7.server.Server',
          methodName: 'handle' },
        { fileName: 'AbstractHttpConnection.java',
          lineNumber: 452,
          className: 'org.seleniumhq.jetty7.server.AbstractHttpConnection',
          methodName: 'handleRequest' },
        { fileName: 'BlockingHttpConnection.java',
          lineNumber: 47,
          className: 'org.seleniumhq.jetty7.server.BlockingHttpConnection',
          methodName: 'handleRequest' },
        { fileName: 'AbstractHttpConnection.java',
          lineNumber: 903,
          className: 'org.seleniumhq.jetty7.server.AbstractHttpConnection',
          methodName: 'messageComplete' },
        { fileName: 'AbstractHttpConnection.java',
          lineNumber: 960,
          className: 'org.seleniumhq.jetty7.server.AbstractHttpConnection$RequestHandler',
          methodName: 'messageComplete' },
        { fileName: 'HttpParser.java',
          lineNumber: 897,
          className: 'org.seleniumhq.jetty7.http.HttpParser',
          methodName: 'parseNext' },
        { fileName: 'HttpParser.java',
          lineNumber: 235,
          className: 'org.seleniumhq.jetty7.http.HttpParser',
          methodName: 'parseAvailable' },
        { fileName: 'BlockingHttpConnection.java',
          lineNumber: 66,
          className: 'org.seleniumhq.jetty7.server.BlockingHttpConnection',
          methodName: 'handle' },
        { fileName: 'SocketConnector.java',
          lineNumber: 254,
          className: 'org.seleniumhq.jetty7.server.bio.SocketConnector$ConnectorEndPoint',
          methodName: 'run' },
        { fileName: 'QueuedThreadPool.java',
          lineNumber: 599,
          className: 'org.seleniumhq.jetty7.util.thread.QueuedThreadPool',
          methodName: 'runJob' },
        { fileName: 'QueuedThreadPool.java',
          lineNumber: 534,
          className: 'org.seleniumhq.jetty7.util.thread.QueuedThreadPool$3',
          methodName: 'run' },
        { fileName: 'Thread.java',
          lineNumber: 695,
          className: 'java.lang.Thread',
          methodName: 'run' } ] } }
LOG    - Completed command session
INFO FINISHED
OK. 2 assertions passed.