ApplicationRunner doesn't shut down properly if connection fails before handshake completes

I have a crossbar.io instance running behind an nginx with the current config:

   upstream websocket {
      server 127.0.0.1:8080;
   }
   map $http_upgrade $connection_upgrade {
     default upgrade;
     ''      close;
   }
   server {
   ...
    location = /ws {
        # switch off logging
        access_log off;
        auth_basic off;

        # redirect all HTTP traffic to localhost:8080
        proxy_pass http://websocket;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Scheme $scheme;
        proxy_set_header Host localhost:8080;

        # WebSocket support (nginx 1.4)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
    }
}

Taking as example https://github.com/crossbario/autobahn-python/blob/master/examples/twisted/wamp/app/hello/hello.py
with small modifications (changing the url port)

If crossbar.io is running before the application is started, everything works perfectly.

But if crossbar is down the moment the app begins I got the following response and the application never ends (the reactor is not stopped even if I add the onDisconnect event)

2015-12-01 16:38:16+0000 [-] Log opened.
2015-12-01 16:38:16+0000 [-] Starting factory <autobahn.twisted.websocket.WampWebSocketClientFactory object at 0x7f490d3f3110>
2015-12-01 16:38:16+0000 [-]
    [('debug', True, 'WampWebSocketClientFactory'),
     ('debugCodePaths', False, 'WampWebSocketClientFactory'),
     ('logOctets', True, 'WampWebSocketClientFactory'),
     ('logFrames', True, 'WampWebSocketClientFactory'),
     ('trackTimings', False, 'WampWebSocketClientFactory'),
     ('allowHixie76', False, 'WampWebSocketClientFactory'),
     ('utf8validateIncoming', True, 'WampWebSocketClientFactory'),
     ('applyMask', True, 'WampWebSocketClientFactory'),
     ('maxFramePayloadSize', 0, 'WampWebSocketClientFactory'),
     ('maxMessagePayloadSize', 0, 'WampWebSocketClientFactory'),
     ('autoFragmentSize', 0, 'WampWebSocketClientFactory'),
     ('failByDrop', True, 'WampWebSocketClientFactory'),
     ('echoCloseCodeReason', False, 'WampWebSocketClientFactory'),
     ('openHandshakeTimeout', 5, 'WampWebSocketClientFactory'),
     ('closeHandshakeTimeout', 1, 'WampWebSocketClientFactory'),
     ('tcpNoDelay', True, 'WampWebSocketClientFactory'),
     ('autoPingInterval', 0, 'WampWebSocketClientFactory'),
     ('autoPingTimeout', 0, 'WampWebSocketClientFactory'),
     ('autoPingSize', 4, 'WampWebSocketClientFactory'),
     ('version', 18, 'WampWebSocketClientFactory'),
     ('acceptMaskedServerFrames', False, 'WampWebSocketClientFactory'),
     ('maskClientFrames', True, 'WampWebSocketClientFactory'),
     ('serverConnectionDropTimeout', 1, 'WampWebSocketClientFactory'),
     ('perMessageCompressionOffers', [], 'WampWebSocketClientFactory'),
     ('perMessageCompressionAccept',
      <function <lambda> at 0x7f490e2e9758>,
      'WampWebSocketClientFactory')]
2015-12-01 16:38:16+0000 [-] connection to tcp4:127.0.0.1:80 established
2015-12-01 16:38:16+0000 [-] TX Octets to tcp4:127.0.0.1:80 : sync = False, octets = 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
2015-12-01 16:38:16+0000 [-] GET /ws HTTP/1.1
    User-Agent: AutobahnPython/0.10.9
    Host: 127.0.0.1:80
    Upgrade: WebSocket
    Connection: Upgrade
    Pragma: no-cache
    Cache-Control: no-cache
    Sec-WebSocket-Key: m04wyOtpm0tfwGYVGsVxtQ==
    Sec-WebSocket-Protocol: wamp.2.json.batched,wamp.2.json
    Sec-WebSocket-Version: 13


2015-12-01 16:38:16+0000 [-] RX Octets from tcp4:127.0.0.1:80 : octets = 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
2015-12-01 16:38:16+0000 [-] received HTTP response:

    HTTP/1.1 502 Bad Gateway
    Server: nginx/1.6.2
    Date: Tue, 01 Dec 2015 16:38:16 GMT
    Content-Type: text/html
    Content-Length: 172
    Connection: keep-alive




2015-12-01 16:38:16+0000 [-] received HTTP status line in opening handshake : HTTP/1.1 502 Bad Gateway
2015-12-01 16:38:16+0000 [-] Unable to format event {'log_namespace': 'autobahn.twisted.websocket.WampWebSocketClientFactory', 'log_level': <LogLevel=debug>, 'format': '%(log_legacy)s', 'time': 1448987896.668816, 'log_source': <autobahn.twisted.websocket.WampWebSocketClientFactory object at 0x7f490d3f3110>, 'log_format': "received HTTP headers in opening handshake : {u'date': u'Tue, 01 Dec 2015 16:38:16 GMT', u'content-length': u'172', u'content-type': u'text/html', u'connection': u'keep-alive', u'server': u'nginx/1.6.2'}", 'system': '-', 'log_logger': <Logger 'autobahn.twisted.websocket.WampWebSocketClientFactory'>, 'message': (), 'log_time': 1448987896.668816}: u"u'date'"
2015-12-01 16:38:16+0000 [-] failing WebSocket opening handshake ('WebSocket connection upgrade failed (502 - BadGateway)')
2015-12-01 16:38:16+0000 [-] Connection to/from tcp4:127.0.0.1:80 was aborted locally
2015-12-01 16:38:16+0000 [-] Stopping factory <autobahn.twisted.websocket.WampWebSocketClientFactory object at 0x7f490d3f3110>

Start with the Twisted WAMP ApplicationRunner path shown by the hello.py example and reproduce the failure while Crossbar is unavailable. Trace the failed opening handshake and shutdown callbacks; done means the application terminates cleanly and the reactor stops after the connection failure.