azure-cli: `az ad user show` has an error when used with guest AAD account

When I try to use az ad user show with a guest account, I get an error stating The specified api-version is invalid

az ad user show --upn-or-object-id 'testuser1_nobun.onmicrosoft.com#EXT#@microsoft.onmicrosoft.com'
The specified api-version is invalid. The value must exactly match a supported version.
Traceback (most recent call last):
  File "/opt/az/lib/python3.6/site-packages/azure/cli/main.py", line 36, in main
    cmd_result = APPLICATION.execute(args)
  File "/opt/az/lib/python3.6/site-packages/azure/cli/core/application.py", line 212, in execute
    result = expanded_arg.func(params)
  File "/opt/az/lib/python3.6/site-packages/azure/cli/core/commands/__init__.py", line 377, in __call__
    return self.handler(*args, **kwargs)
  File "/opt/az/lib/python3.6/site-packages/azure/cli/core/commands/__init__.py", line 630, in _execute_command
    raise client_exception
  File "/opt/az/lib/python3.6/site-packages/azure/cli/core/commands/__init__.py", line 618, in _execute_command
    exception_handler(ex)
  File "/opt/az/lib/python3.6/site-packages/azure/cli/core/util.py", line 49, in empty_on_404
    raise ex
  File "/opt/az/lib/python3.6/site-packages/azure/cli/core/commands/__init__.py", line 602, in _execute_command
    result = op(client, **kwargs) if client else op(**kwargs)
  File "/opt/az/lib/python3.6/site-packages/azure/graphrbac/operations/users_operations.py", line 220, in get
    raise models.GraphErrorException(self._deserialize, response)
azure.graphrbac.models.graph_error.GraphErrorException: The specified api-version is invalid. The value must exactly match a supported version.

az ad user list is an acceptable workaround, so this is a non-blocking issue

az ad user list --upn 'testuser1_nobun.onmicrosoft.com#EXT#@microsoft.onmicrosoft.com'

az ad user show for a member originating in the same tenant works, so this seems to be isolated to certain accounts:

az ad user show --upn-or-object-id 'nobun@microsoft.com'

---

Environment summary

apt-get / 2.0.20 / Windows 10 Build 17017 / Bash on Windows

Full version info:

azure-cli (2.0.20)

acr (2.0.14)
acs (2.0.18)
appservice (0.1.19)
backup (1.0.2)
batch (3.1.6)
batchai (0.1.2)
billing (0.1.6)
cdn (0.0.10)
cloud (2.0.9)
cognitiveservices (0.1.9)
command-modules-nspkg (2.0.1)
component (2.0.8)
configure (2.0.12)
consumption (0.1.6)
container (0.1.12)
core (2.0.20)
cosmosdb (0.1.14)
dla (0.0.13)
dls (0.0.16)
eventgrid (0.1.5)
extension (0.0.5)
feedback (2.0.6)
find (0.2.7)
interactive (0.3.11)
iot (0.1.13)
keyvault (2.0.13)
lab (0.0.12)
monitor (0.0.11)
network (2.0.17)
nspkg (3.0.1)
profile (2.0.15)
rdbms (0.0.8)
redis (0.2.10)
resource (2.0.17)
role (2.0.14)
servicefabric (0.0.5)
sql (2.0.14)
storage (2.0.18)
vm (2.0.17)

Python location '/opt/az/bin/python3'
Extensions directory '/home/noel/.azure/cliextensions'

Python (Linux) 3.6.1 (default, Oct 18 2017, 20:41:18)
[GCC 4.8.4]

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