cluster_connect intermittently failing with 400 bad request error

Traceback (most recent call last):

 File "./cluster_connect", line 108, in <module>

 main()

 File "./cluster_connect", line 103, in main

 cluster_run_lib.connect(**params)

 File "/opt/build/ns_server/pylib/cluster_run_lib.py", line 659, in connect

 addr, port), data).read()

 File "/usr/local/lib/python3.7/urllib/request.py", line 531, in open

 response = meth(req, response)

 File "/usr/local/lib/python3.7/urllib/request.py", line 641, in http_response

 'http', request, response, code, msg, hdrs)

 File "/usr/local/lib/python3.7/urllib/request.py", line 569, in error

 return self._call_chain(*args)

 File "/usr/local/lib/python3.7/urllib/request.py", line 503, in _call_chain

 result = func(*args)

 File "/usr/local/lib/python3.7/urllib/request.py", line 649, in http_error_default

 raise HTTPError(req.full_url, code, msg, hdrs, fp)

urllib.error.HTTPError: HTTP Error 400: Bad Request

Connecting 2 nodes, bucket type membase, mem size 1500 with 1 replica copies, password asdasd, deployment plan {'n0': ['kv', 'n1ql'], 'n1': ['kv', 'index']}

Connecting node 0 with services ['kv', 'n1ql']

Connecting node 1 with services ['kv', 'index']

Error 400: Bad Request (b'["Got HTTP status 500 from REST call post to https://127.0.0.1:19000/controller/addNodeV2. Body was: \\"[\\\\\\"Unexpected server error, request logged.\\\\\\"]\\""]')