Probably related to #1643 , but what appears to happen seems different (at least the error is).

From what I can see, the lambda executes successfully, but then fails to return the result, returning the following instead:
```json
{
    "Type": "Server",
    "message": "Error executing Lambda function arn:aws:lambda:ap-northeast-1:000000000000:function:service-stage-functionName: module 'botocore.errorfactory' has no attribute 'ResourceAlreadyExistsException' Traceback (most recent call last):\n  File \"/opt/code/localstack/localstack/services/awslambda/lambda_executors.py\", line 106, in _store_logs\n    logs_client.create_log_group(logGroupName=log_group_name)\n  File \"/opt/code/localstack/.venv/lib/python3.6/site-packages/botocore/client.py\", line 357, in _api_call\n    return self._make_api_call(operation_name, kwargs)\n  File \"/opt/code/localstack/.venv/lib/python3.6/site-packages/botocore/client.py\", line 661, in _make_api_call\n    raise error_class(parsed_response, operation_name)\nbotocore.errorfactory.ResourceAlreadyExistsException: An error occurred (ResourceAlreadyExistsException) when calling the CreateLogGroup operation: The specified log group already exists\n\nDuring handling of the above exception, another exception occurred:\n\nTraceback (most recent call last):\n  File \"/opt/code/localstack/localstack/services/awslambda/lambda_api.py\", line 339, in run_lambda\n    event, context=context, version=version, asynchronous=asynchronous)\n  File \"/opt/code/localstack/localstack/services/awslambda/lambda_executors.py\", line 81, in execute\n    return do_execute()\n  File \"/opt/code/localstack/localstack/services/awslambda/lambda_executors.py\", line 70, in do_execute\n    self._store_logs(func_details, log_output, invocation_time)\n  File \"/opt/code/localstack/localstack/services/awslambda/lambda_executors.py\", line 107, in _store_logs\n    except botocore.errorfactory.ResourceAlreadyExistsException:\nAttributeError: module 'botocore.errorfactory' has no attribute 'ResourceAlreadyExistsException'\n",
    "__type": "InternalFailure"
}
```

Looking at the localstack end I see the following log:

```
...(lambda execution log, SUCCESS etc)...
> REPORT RequestId: 00e1e000-0e00-000c-0000-8ccf00ab00ba	Duration: 52.74 ms	Billed Duration: 100 ms	Memory Size: 1536 MB	Max Memory Used: 5 MB	
> nohup: failed to run command 'python': No such file or directory
2019-10-25T11:46:25:WARNING:localstack.services.awslambda.lambda_api: Error executing Lambda function arn:aws:lambda:ap-northeast-1:000000000000:function:service-stage-functionName: module 'botocore.errorfactory' has no attribute 'ResourceAlreadyExistsException' Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 106, in _store_logs
    logs_client.create_log_group(logGroupName=log_group_name)
  File "/opt/code/localstack/.venv/lib/python3.6/site-packages/botocore/client.py", line 357, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/opt/code/localstack/.venv/lib/python3.6/site-packages/botocore/client.py", line 661, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.errorfactory.ResourceAlreadyExistsException: An error occurred (ResourceAlreadyExistsException) when calling the CreateLogGroup operation: The specified log group already exists

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/awslambda/lambda_api.py", line 339, in run_lambda
    event, context=context, version=version, asynchronous=asynchronous)
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 81, in execute
    return do_execute()
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 70, in do_execute
    self._store_logs(func_details, log_output, invocation_time)
  File "/opt/code/localstack/localstack/services/awslambda/lambda_executors.py", line 107, in _store_logs
    except botocore.errorfactory.ResourceAlreadyExistsException:
AttributeError: module 'botocore.errorfactory' has no attribute 'ResourceAlreadyExistsException'
```

Will update if I am able to create an easily reproducible case!
event_file = EVENT_FILE_PATTERN.replace('*', short_uid())
        save_file(event_file, json.dumps(event))
        TMP_FILES.append(event_file)
        class_name = handler.split('::')[0]
        classpath = '%s:%s' % (LAMBDA_EXECUTOR_JAR, main_file)
        cmd = 'java -cp %s %s %s %s' % (classpath, LAMBDA_EXECUTOR_CLASS, class_name, event_file)
        result, log_output = self.run_lambda_executor(cmd)
        LOG.debug('Lambda result / log output:\n%s\n> %s' % (
            result.strip(), log_output.strip().replace('\n', '\n> ')))
        return result, log_output
class Util:
    debug_java_port = False
    @classmethod
    def get_java_opts(cls):
        opts = config.LAMBDA_JAVA_OPTS or ''
        if '_debug_port_' in opts:
            if not cls.debug_java_port:
                cls.debug_java_port = get_free_tcp_port()
            opts = opts.replace('_debug_port_', ('%s' % cls.debug_java_port))
        return opts
EXECUTOR_LOCAL = LambdaExecutorLocal()
EXECUTOR_CONTAINERS_SEPARATE = LambdaExecutorSeparateContainers()
EXECUTOR_CONTAINERS_REUSE = LambdaExecutorReuseContainers()
DEFAULT_EXECUTOR = EXECUTOR_LOCAL
AVAILABLE_EXECUTORS = {
    'local': EXECUTOR_LOCAL,
    'docker': EXECUTOR_CONTAINERS_SEPARATE,
    'docker-reuse': EXECUTOR_CONTAINERS_REUSE
}