A short look through the stacktrace actually seemed to have gotten me to the issue. It is in the xmlrpc.client library in this piece of code:

         for i in (0, 1):
             try:
                 return self.single_request(host, handler, request_body, verbose)
             except OSError as e:
                 if i or e.errno not in (errno.ECONNRESET, errno.ECONNABORTED,
                                         errno.EPIPE):
                     raise
             except http.client.RemoteDisconnected:
                 if i:
                     raise

As can be seen http.client.RemoteDisconnected error is caught after the OSError one. However http.client.RemoteDisconnected is a subclass of OSError since it's a subclass of ConnectionResetError: https://docs.python.org/3/library/http.client.html#http.client.RemoteDisconnected

A simple fix which seems to work for me is switching the two except branches as I did in the attached patch.