We’re trying to prerender our site for bots and update the pre-rendered versions immediately upon changes to the site. I see from the docs that the basic pre-render service can take 24-48 hours to update pre-rendered pages. In order to avoid this wait time, we are considering using an external service like prerender.io. But we wondered, would the CDN still serve old cached pre-rendered pages previously retrieved from the external service. If so, is there any way to invalidate these?