Unhandled Error on disconnect

[ln5]

Possibly related to #70, I see this (in addition to the backtrace in #70):

2018-02-05T16:04:48+0100 [INFO]: Downloading file '4M' over [$771E0824EF82D85E04D80116554111E37F7EB796, $A3CB2E3D24A1688DC7213988B1BE9321B62AAD8C].
Unhandled Error
Traceback (most recent call last):
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 916, in dispatcher
return func(*args, **kwargs)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1480, in _finishResponse_WAITING
self._giveUp(Failure(reason))
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1533, in _giveUp
self._disconnectParser(reason)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1521, in _disconnectParser
parser.connectionLost(reason)
--- ---
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 537, in connectionLost
self.response._bodyDataFinished()
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 916, in dispatcher
return func(*args, **kwargs)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1169, in _bodyDataFinished_CONNECTED
self._bodyProtocol.connectionLost(reason)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/client.py", line 2113, in connectionLost
self.deferred.callback(b''.join(self.dataBuffer))
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 393, in callback
self._startRunCallbacks(result)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 494, in _startRunCallbacks
raise AlreadyCalledError
twisted.internet.defer.AlreadyCalledError:

2018-02-05T16:04:56+0100 [CRITICAL]: Unhandled Error
Traceback (most recent call last):
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 916, in dispatcher
return func(*args, **kwargs)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1480, in _finishResponse_WAITING
self._giveUp(Failure(reason))
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1533, in _giveUp
self._disconnectParser(reason)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1521, in _disconnectParser
parser.connectionLost(reason)
--- ---
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 537, in connectionLost
self.response._bodyDataFinished()
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 916, in dispatcher
return func(*args, **kwargs)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/_newclient.py", line 1169, in _bodyDataFinished_CONNECTED
self._bodyProtocol.connectionLost(reason)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/web/client.py", line 2113, in connectionLost
self.deferred.callback(b''.join(self.dataBuffer))
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 393, in callback
self._startRunCallbacks(result)
File "/home/bwscanner/.local/lib/python2.7/site-packages/Twisted-16.2.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 494, in _startRunCallbacks
raise AlreadyCalledError
twisted.internet.defer.AlreadyCalledError:

Pasting two backtraces here since I'm not sure what lines before and after the backtrace belong to which backtrace.