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 :) 
return o if o is None else json.dumps(o) if isinstance(o, (dict, list)) else str(o)
def select_attributes(obj, attrs):
    result = {}
    for attr in attrs:
        if obj.get(attr) is not None:
            result[attr] = str_or_none(obj.get(attr))
    return result
def get_bucket_location_config(**kwargs):
    return {'LocationConstraint': aws_stack.get_region()}
def lambda_get_params():
    return lambda params, **kwargs: params
def rename_params(func, rename_map):
    def do_rename(params, **kwargs):
        values = func(params, **kwargs) if func else params
        for old_param, new_param in rename_map.items():
            values[new_param] = values.pop(old_param, None)
        return values
    return do_rename
def params_list_to_dict(param_name, key_attr_name, value_attr_name):
    def do_replace(params, **kwargs):
        result = {}
        for entry in params.get(param_name, []):
            key = entry[key_attr_name]
            value = entry[value_attr_name]
            result[key] = value
        return result
    return do_replace
def get_nested_stack_params(params, **kwargs):