Sometimes, attempting to run lambdas will return this type of error:
```
{"Type": "Server", "message": "Error executing Lambda function arn:aws:lambda:ap-northeast-1:000000000000:function:service-stage-functionName: An error occurred (ResourceAlreadyExistsException) when calling the CreateLogGroup operation: The specified log group already exists Traceback (most recent call last):\n 
File \"/opt/code/localstack/localstack/services/awslambda/lambda_api.py\", line 338, 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 105, 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)\n
botocore.errorfactory.ResourceAlreadyExistsException: An error occurred (ResourceAlreadyExistsException) when calling the CreateLogGroup operation: The specified log group already exists\n", "__type": "InternalFailure"}
```
I am not yet sure if there are any particular settings that cause it, since it does not occur for certain deployments.

Will update if I can figure out the exact configuration.
s3_client = aws_stack.connect_to_service('s3')
        value = b''
        if bucket_name != BUCKET_MARKER_LOCAL:
            value = s3_client.get_object(Bucket=bucket_name, Key=key_name)['Body'].read()
        return s3_models.FakeKey(name=key_name, value=value)
    s3_models.S3Backend.get_key = get_key
    
    def clean_json(resource_json, resources_map):
        result = clean_json_orig(resource_json, resources_map)
        if isinstance(result, BaseModel):
            if isinstance(resource_json, dict) and 'Ref' in resource_json:
                entity_id = get_entity_id(result, resource_json)
                if entity_id:
                    return entity_id
                LOG.warning('Unable to resolve "Ref" attribute for: %s - %s - %s',
                            resource_json, result, type(result))
        return result
    clean_json_orig = parsing.clean_json
    parsing.clean_json = clean_json
    
    parsing.MODEL_MAP.update(MODEL_MAP)
    
    def parse_and_create_resource(logical_id, resource_json, resources_map, region_name):