intermittent gRPC "channel closed!" error when no data is returned from device

[lucasalvatore]

pygnmi version = 0.8.15
Python version = 3.10.12
device = nokia 7750 (sros 23.10)

When subscribing once (the only way SROS will work afaik) if a particular path does not return any data, i'm seeing an intermittent gRPC error

in this example ports 1/1/c27/1 and 1/1/c28/1 do not exist on the device

subscribe_request = {'subscription': [{'path': 'state/port[port-id=1/1/c27/1]/oper-state/'},
  {'path': 'state/port[port-id=1/1/c28/1]/oper-state/'}],
 'mode': 'ONCE',
 'encoding': 'json'}

for _ in range(10):
     try:
         with gNMIclient(target=host, username="foo", password=grpc_password, insecure=True, timeout=20) as client:
             responses = list(client.subscribe2(subscribe_request))
     except Exception as e:
        print(e)
     print("SUCCESS", responses)
     print()

when running this loop, sometimes it works, sometimes it throws the error below:

SUCCESS [{'sync_response': True}]

Exception in thread Thread-194 (enqueue_updates):
Traceback (most recent call last):
  File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.10/threading.py", line 953, in run
    self._target(*self._args, **self._kwargs)
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/pygnmi/client.py", line 1080, in enqueue_updates
    raise error
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/pygnmi/client.py", line 1076, in enqueue_updates
    for update in subscription:
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/grpc/_channel.py", line 543, in __next__
    return self._next()
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/grpc/_channel.py", line 969, in _next
    raise self
grpc._channel._MultiThreadedRendezvous: <_MultiThreadedRendezvous of RPC that terminated with:
	status = StatusCode.CANCELLED
	details = "Channel closed!"
	debug_error_string = "UNKNOWN:Error received from peer  {created_time:"2025-04-16T11:32:30.797396803-04:00", grpc_status:1, grpc_message:"Channel closed!"}"
>
SUCCESS [{'sync_response': True}]

SUCCESS [{'sync_response': True}]

Exception in thread Thread-208 (enqueue_updates):
Traceback (most recent call last):
  File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.10/threading.py", line 953, in run
    self._target(*self._args, **self._kwargs)
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/pygnmi/client.py", line 1080, in enqueue_updates
    raise error
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/pygnmi/client.py", line 1076, in enqueue_updates
    for update in subscription:
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/grpc/_channel.py", line 543, in __next__
    return self._next()
  File "/home/lsalvatore/venvs/python3/lib/python3.10/site-packages/grpc/_channel.py", line 969, in _next
    raise self
grpc._channel._MultiThreadedRendezvous: <_MultiThreadedRendezvous of RPC that terminated with:
	status = StatusCode.CANCELLED
	details = "Channel closed!"
	debug_error_string = "UNKNOWN:Error received from peer  {created_time:"2025-04-16T11:32:31.968167337-04:00", grpc_status:1, grpc_message:"Channel closed!"}"
>
SUCCESS [{'sync_response': True}]

I never see this when asking for ports that do exist.