What Happens When A User Edits A Post on Dev.to?

I am catching up on Ben’s posts on web perf and I still don’t quite get what happens when a post is edited. I understand that things are cached but doesn’t that mean that if a post is edited it will take an unpredictable amount of time to update to CDNs all around the world? What are the best practices around this? Does it cost anything to do this? These are the kinds of questions I have when wondering about what I would run into if I were to make a dev.to clone.