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 :) 
response = Response()
    response.status_code = code
    response.headers['x-amzn-errortype'] = error_type
    response._content = """<ErrorResponse xmlns="%s">
          <Error>
            <Type>Sender</Type>
            <Code>%s</Code>
            <Message>%s</Message>
          </Error>
          <RequestId>%s</RequestId>
        </ErrorResponse>""" % (XMLNS_CLOUDFORMATION, error_type, message, uuid.uuid4())
    return response
def make_response(operation_name, content='', code=200):
    response = Response()
    response._content = """<{op_name}Response xmlns="{xmlns}">
      <{op_name}Result>
        {content}
      </{op_name}Result>
      <ResponseMetadata><RequestId>{uid}</RequestId></ResponseMetadata>
    </{op_name}Response>""".format(xmlns=XMLNS_CLOUDFORMATION,
        op_name=operation_name, uid=uuid.uuid4(), content=content)
    response.status_code = code
    return response
def validate_template(req_data):