It looks like a duplicate of old issue https://github.com/localstack/localstack/issues/78
But now it's reproducible for me with the latest version of LocalStack. 
queue_url = self._queue_url(path, req_data, headers)
        attrs = self._format_attributes(req_data)
        
        attrs = dict([(k, v) for k, v in attrs.items() if k in UNSUPPORTED_ATTRIBUTE_NAMES])
        QUEUE_ATTRIBUTES[queue_url] = QUEUE_ATTRIBUTES.get(queue_url) or {}
        QUEUE_ATTRIBUTES[queue_url].update(attrs)
    def _add_queue_attributes(self, path, req_data, content_str, headers):