Durante o processo de raspagem usando raspagem, um erro aparece nos meus logs de tempos em tempos. Ele não parece estar em nenhum lugar do meu código e parece algo dentro de twisted \ openssl. Alguma idéia do que causou isso e como se livrar dele?

Stacktrace aqui:

[Launcher,27487/stderr] Error during info_callback
    Traceback (most recent call last):
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/twisted/protocols/tls.py", line 415, in dataReceived
        self._write(bytes)
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/twisted/protocols/tls.py", line 554, in _write
        sent = self._tlsConnection.send(toSend)
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/OpenSSL/SSL.py", line 1270, in send
        result = _lib.SSL_write(self._ssl, buf, len(buf))
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/OpenSSL/SSL.py", line 926, in wrapper
        callback(Connection._reverse_mapping[ssl], where, return_code)
    --- <exception caught here> ---
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/twisted/internet/_sslverify.py", line 1055, in infoCallback
        return wrapped(connection, where, ret)
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/twisted/internet/_sslverify.py", line 1157, in _identityVerifyingInfoCallback
        transport = connection.get_app_data()
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/OpenSSL/SSL.py", line 1589, in get_app_data
        return self._app_data
      File "/opt/webapps/link_crawler/lib/python2.7/site-packages/OpenSSL/SSL.py", line 1148, in __getattr__
        return getattr(self._socket, name)
    exceptions.AttributeError: 'NoneType' object has no attribute '_app_data'