May be a duplicate of https://github.com/localstack/localstack/issues/988 but due to the age I will re raise.

I'm having issues when I throw an exception in a lambda - it isn't appearing on my dead letter queue. Is there something I am missing, I would like an sqs event exception to appear on the poison queue when an exception happens.

Below is the basic config:
 ````
    sqsclient.create_queue(QueueName = 'test-queue')
    sqsclient.create_queue(QueueName = 'test-queue-poison')

    lambda_client.create_function(
            FunctionName='MyFunction',
            Runtime='dotnetcore2.1',
            Role='role',
            Handler='Handler',
            Code=code,
	    DeadLetterConfig={'TargetArn': 'test-queue-poison-arn'})

     lambda_client.create_event_source_mapping(
		EventSourceArn='test-queue-arn',
		FunctionName='MyFunction',
		Enabled=True,
		BatchSize=100,
		StartingPosition='LATEST')
````

So when I raise a new (.net)exception within the lambda function no message is going to the dead letter queue. I can confirm that all is attached together OK as all other scenarios work, and the above code is pseudo-ish.
aws_stack.create_kinesis_stream(self.TEST_STREAM_KINESIS_API_GW)
        
        result = self.connect_api_gateway_to_kinesis('test_gateway1', self.TEST_STREAM_KINESIS_API_GW)
        
        test_data = {'records': [
            {'data': '{"foo": "bar1"}'},
            {'data': '{"foo": "bar2"}'},
            {'data': '{"foo": "bar3"}'}
        ]}
        url = self.gateway_request_url(
            api_id=result['id'],
            stage_name=self.TEST_STAGE_NAME,
            path=self.API_PATH_DATA_INBOUND
        )
        
        result = requests.get(url)
        result = json.loads(to_str(result.content))
        self.assertIn('StreamNames', result)
        
        result = requests.post(url, data=json.dumps(test_data))
        result = json.loads(to_str(result.content))
        self.assertEqual(result['FailedRecordCount'], 0)
        self.assertEqual(len(result['Records']), len(test_data['records']))
        
        kinesis = aws_stack.connect_to_service('kinesis')
        kinesis.delete_stream(StreamName=self.TEST_STREAM_KINESIS_API_GW)