pyVmomi.SoapAdapter.ParserError: xml document parse error

I get this error when querying the vSAN health summary. I'm using pyVmomi version 6.7.1.2018.12

Traceback (most recent call last):
  File "/usr/share/java/pycharm-community/helpers/pydev/pydevd.py", line 1741, in <module>
    main()
  File "/usr/share/java/pycharm-community/helpers/pydev/pydevd.py", line 1735, in main
    globals = debugger.run(setup['file'], None, None, is_module)
  File "/usr/share/java/pycharm-community/helpers/pydev/pydevd.py", line 1135, in run
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/home/juan/devel/scripts/vmware/vsan-get-disk-health.py", line 75, in <module>
    cluster=cluster, includeObjUuids=True, fetchFromCache=True)
  File "/home/juan/.local/lib/python2.7/site-packages/pyVmomi/VmomiSupport.py", line 706, in <lambda>
    self.f(*(self.args + (obj,) + args), **kwargs)
  File "/home/juan/.local/lib/python2.7/site-packages/pyVmomi/VmomiSupport.py", line 512, in _InvokeMethod
    return self._stub.InvokeMethod(self, info, args)
  File "/home/juan/.local/lib/python2.7/site-packages/pyVmomi/SoapAdapter.py", line 1365, in InvokeMethod
    raise exc
pyVmomi.SoapAdapter.ParserError: 'xml document: <pyVmomi.SoapAdapter.GzipReader instance at 0x7facf6235b00> parse error at: line:2, col:29212'

Debugging the code I see that the response is chunked and only gets a fragment of the xml. That could be the reason of the incorrect parsing? or am I doing something wrong?

This is a fragment of the code I'm running, it fails at the line healthSummary = vhs.QueryClusterHealthSummary(...)

vc = {"host": "vcenter.example.com",
      "port": 443,
      "user": "Administrator@vsphere.local",
      "password": "123456",
      }
clusters = ["Cluster 1", "Cluster 2"]
context = ssl.create_default_context()
context.check_hostname = False
context.verify_mode = ssl.CERT_NONE
si = SmartConnect(host=vc["host"],
                  user=vc["user"],
                  pwd=vc["password"],
                  port=vc["port"],
                  sslContext=context)
if not si:
    sys.exit("Could not connect to {h}".format(h=vc["host"]))
atexit.register(Disconnect, si)

# Detecting whether the host is vCenter or ESXi.
aboutInfo = si.content.about
apiVersion = vsanapiutils.GetLatestVmodlVersion(vc["host"])
if aboutInfo.apiType == 'VirtualCenter':
    majorApiVersion = aboutInfo.apiVersion.split('.')[0]
    if int(majorApiVersion) < 6:
        print('The Virtual Center with version %s (lower than 6.0) is not supported.'
              % aboutInfo.apiVersion)
        sys.exit(-1)

# Get vSAN health system from the vCenter Managed Object references.
vcMos = vsanapiutils.GetVsanVcMos(
    si._stub, context=context, version=apiVersion)

vhs = vcMos['vsan-cluster-health-system']
for c in clusters:
    cluster = getClusterInstance(c, si)
    healthSummary = vhs.QueryClusterHealthSummary(
        cluster=cluster, includeObjUuids=True, fetchFromCache=True)
    clusterStatus = healthSummary.clusterStatus

    print("Cluster %s Status: %s" % (c, clusterStatus.status))
    for hostStatus in clusterStatus.trackedHostsStatus:
        print("Host %s Status: %s" % (hostStatus.hostname, hostStatus.status))

Start with pyVmomi/SoapAdapter.py at InvokeMethod and the GzipReader referenced by the traceback, then review VmomiSupport.py around the call path. Reproduce the vSAN QueryClusterHealthSummary request using the supplied example and inspect how its chunked response is handled. Done means the parsing failure is explained and a verified fix or clear reproduction boundary is established.