I discussed this ~7 months ago in comments to another article. https://news.ycombinator.com/item?id=23627864 https://news.ycombinator.com/item?id=23627864 Par

I discussed this ~7 months ago in comments to another article. https://news.ycombinator.com/item?id=23627864 https://news.ycombinator.com/item?id=23627864 Part of it seemed to be that I was querying an anycast server, the Google DNS server 8.8.8.8, which is probably many servers. So I wasn't hitting a cached entry because I was hitting a new server. There are cache invalidation processes, the BIND name server has had one for ~20 years between authoritative servers. Google and Cloud Flare provide mechanisms for you to submit your own invalidation requests on a zone, and one could imagine a big provider like AWS doing that. See the discussions in the above thread for more links to how to test and invalidate.