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.
' %s %s'  
                ')";'
                '%s cp "%s/." "$CONTAINER_ID:/var/task"; '
                '%s start -ai "$CONTAINER_ID";'
            ) % (docker_cmd, entrypoint, debug_docker_java_port, env_vars_string, network_str, rm_flag,
                 docker_image, command,
                 docker_cmd, lambda_cwd,
                 docker_cmd)
        else:
            lambda_cwd_on_host = Util.get_host_path_for_path_in_docker(lambda_cwd)
            cmd = (
                '%s run -i'
                ' %s -v "%s":/var/task'
                ' %s'
                ' %s'  
                ' %s'  
                ' %s %s'
            ) % (docker_cmd, entrypoint, lambda_cwd_on_host, env_vars_string,
                 network_str, rm_flag, docker_image, command)
        return cmd
class LambdaExecutorLocal(LambdaExecutor):
    def _execute(self, func_arn, func_details, event, context=None, version=None):
        lambda_cwd = func_details.cwd
        environment = func_details.envvars.copy()
        
        queue = Queue()
        lambda_function = func_details.function(version)
        def do_execute():
            
            if lambda_cwd: