"'NoneType' object is not subscriptable" error importing pool

[Aero-Graphics]

I've started having a weird error on one of the shared storage systems in my environment. If I try to import any pool from the GUI or API I get the following error:

Code:

Error: Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/middlewared/job.py", line 355, in run
    await self.future
  File "/usr/local/lib/python3.9/site-packages/middlewared/job.py", line 391, in __run_body
    rv = await self.method(*([self] + args))
  File "/usr/local/lib/python3.9/site-packages/middlewared/schema.py", line 981, in nf
    return await f(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/pool.py", line 1458, in import_pool
    await self.middleware.call('pool.scrub.create', {
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1279, in call
    return await self._call(
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1236, in _call
    return await methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.9/site-packages/middlewared/service.py", line 496, in create
    rv = await self.middleware._call(
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1236, in _call
    return await methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.9/site-packages/middlewared/schema.py", line 981, in nf
    return await f(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/pool.py", line 4162, in do_create
    verrors, data = await self.validate_data(data, 'pool_scrub_create')
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/pool.py", line 4108, in validate_data
    scrub_obj = await self.query(filters=[('pool', '=', pool_pk)])
  File "/usr/local/lib/python3.9/site-packages/middlewared/schema.py", line 981, in nf
    return await f(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/middlewared/service.py", line 483, in query
    result = await self.middleware.call(
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1279, in call
    return await self._call(
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1236, in _call
    return await methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.9/site-packages/middlewared/schema.py", line 981, in nf
    return await f(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/datastore/read.py", line 164, in query
    result = await self._queryset_serialize(
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/datastore/read.py", line 214, in _queryset_serialize
    result.append(await self._serialize(
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/datastore/read.py", line 232, in _serialize
    data = await self.middleware.call(extend, data)
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1279, in call
    return await self._call(
  File "/usr/local/lib/python3.9/site-packages/middlewared/main.py", line 1236, in _call
    return await methodobj(*prepared_call.args)
  File "/usr/local/lib/python3.9/site-packages/middlewared/plugins/pool.py", line 4078, in pool_scrub_extend
    data['pool'] = pool['id']
TypeError: 'NoneType' object is not subscriptable

It does not matter what pool I try to import, I will receive this error. If I create a new pool it will mount it just fine, but if I export it I will then get this error. The other shared storage system can import/export the pools without issue.

Any ideas where to look for this?

Rob