Originally reported in https://github.com/localstack/localstack/issues/2099, the CreationTime for CF stacks was hardcoded. This was fixed in in LocalStack itself (https://github.com/localstack/localstack/pull/2103), but is now also fixed in moto (https://github.com/spulec/moto/pull/2818).

I don't know what version of moto you're using, and whether it's acceptable to use dev-releases, but if you do: 

moto 1.3.15.dev550 should fix this issue, so the LS fix can be removed if you upgrade :) 
if stack_name.startswith('arn:aws:cloudformation'):
                        run_fix = True
                        stack_name = re.sub(r'arn:aws:cloudformation:[^:]+:[^:]+:stack/([^/]+)(/.+)?',
                                            r'\1', stack_name)
                if run_fix:
                    stack_names = [stack_name] if stack_name else self._list_stack_names()
                    client = aws_stack.connect_to_service('cloudformation')
                    events = []
                    for stack_name in stack_names:
                        tmp = client.describe_stack_events(StackName=stack_name)['StackEvents'][:1]
                        events.extend(tmp)
                    events = [{'member': e} for e in events]
                    response_content = '<StackEvents>%s</StackEvents>' % obj_to_xml(events)
                    return make_response('DescribeStackEvents', response_content)
        if req_data:
            if action == 'ValidateTemplate':
                return validate_template(req_data)
            if action in ['CreateStack', 'UpdateStack']:
                do_replace_url = is_real_s3_url(req_data.get('TemplateURL'))
                if do_replace_url:
                    req_data['TemplateURL'] = convert_s3_to_local_url(req_data['TemplateURL'])
                modified_request = transform_template(req_data)
                if modified_request:
                    req_data.pop('TemplateURL', None)
                    req_data['TemplateBody'] = json.dumps(modified_request)
                if modified_request or do_replace_url:
                    data = urlparse.urlencode(req_data, doseq=True)
                    return Request(data=data, headers=headers, method=method)
        return True
    def return_response(self, method, path, data, headers, response):