[bug] az iot hub state export fails with KeyError: 'x509Thumbprint'

[Bogdan-Catalin]

Describe the bug
Backing up an IoTHub instance, after running the script for 2h 30mins we get a KeyError: 'x509Thumbprint' crash .

To Reproduce
In our case it was enough to run az iot hub state export --hub-name prod-hub --state-file state.json.

Expected behavior
The statefile should have been generated without errors.

Screenshots
Are full stack traces allowed here ?

Saving devices and modules:  73%|###################################################################################################################                                           | 19903/27177 [2:36:34<57:13,  2.12it/s]
The command failed with an unexpected error. Here is the traceback:
'x509Thumbprint'
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/azure-cli/2.74.0/libexec/lib/python3.12/site-packages/knack/cli.py", line 233, in invoke
    cmd_result = self.invocation.execute(args)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.74.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 666, in execute
    raise ex
  File "/opt/homebrew/Cellar/azure-cli/2.74.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 734, in _run_jobs_serially
    results.append(self._run_job(expanded_arg, cmd_copy))
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.74.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 703, in _run_job
    result = cmd_copy(params)
             ^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.74.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 336, in __call__
    return self.handler(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.74.0/libexec/lib/python3.12/site-packages/azure/cli/core/commands/command_operation.py", line 120, in handler
    return op(**command_args)
           ^^^^^^^^^^^^^^^^^^
  File "/Users/redacteduser/.azure/cliextensions/azure-iot/azext_iot/iothub/commands_state.py", line 29, in state_export
    sp.save_state(state_file, replace, hub_aspects)
  File "/Users/redacteduser/.azure/cliextensions/azure-iot/azext_iot/iothub/providers/state.py", line 102, in save_state
    hub_state = self.process_hub_to_dict(self.target, hub_aspects)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/redacteduser/.azure/cliextensions/azure-iot/azext_iot/iothub/providers/state.py", line 235, in process_hub_to_dict
    devices = self.download_devices(target=target)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/redacteduser/.azure/cliextensions/azure-iot/azext_iot/iothub/providers/state.py", line 591, in download_devices
    module_twin.pop(key)
KeyError: 'x509Thumbprint'
To check existing issues, please visit: https://github.com/Azure/azure-cli/issues

Environment (please complete the following information):

• OS: MacOS 15.5
• Shell: zsh
• Az CLI version: 2.74
• IoT extension version: 0.26.0
• Python version (if pip installed): python 3.12, pip 25.1.1

Additional context
We managed to get this working by modifying here to module_twin.pop(key, None) and for good measure here to module.pop(key, None).

[Elsie4ever]

Thanks for reporting this, will take a look to repro