Don't they have to be pure in order to be idempotent? If you might get a different virtual DOM even when props/state are unchanged (not pure), then re-rendering

Don't they have to be pure in order to be idempotent? If you might get a different virtual DOM even when props/state are unchanged (not pure), then re-rendering the component might update the DOM even when props/state are unchanged (not idempotent).