We just moved our DNS from Network Solutions to Route 53 this month, and I can verify that there are indeed resolvers that'll ignore TTLs. Ours were 3-6 hours, but it took some sites about 24 hours to pick up our new SOA.
Which would have been fine - the A records were the same - but no, NetSol instantly starts serving a blank "Business Profile" landing page A-record. Thanks, people who used to run the Internet.
I know one such caching server was ns1.dns.rcn.net. (But only from inside RCN; querying it from Comcast gave different results. Same IP address, so I'm assuming it's anycast.) whatsmydns.net reported others as "Bell South" and "Cox" (I can't recall the locations, I think one was in Georgia).
Oh, it returned appropriate-looking TTLs even at the time; we didn't watch them go down to zero and wrap to their original value, but I suspect that's what they did.
Also, if you're not on RCN, you aren't getting the same NS1 as someone who is. (Again, I assume anycast or load balancing, but I'm handwaving; I haven't understood routing since gated.conf changed.)
My boss was on RCN at home, and I was a few miles away on Comcast. We both pointed dig at 207.172.3.8 and hammered on our domain name; he saw stale results, I saw fresh ones.
Would've loved to have the expertise and tools set up to figure out what went wrong, but we just went to bed and by lunch it sorted itself out.
I let it cache a record, disabled the zone the record came from and left it to expire. It did. I won't deny that it could behave differently from different addresses, but based on the evidence available I'm sure you can understand why I remain unconvinced.
Which would have been fine - the A records were the same - but no, NetSol instantly starts serving a blank "Business Profile" landing page A-record. Thanks, people who used to run the Internet.
I know one such caching server was ns1.dns.rcn.net. (But only from inside RCN; querying it from Comcast gave different results. Same IP address, so I'm assuming it's anycast.) whatsmydns.net reported others as "Bell South" and "Cox" (I can't recall the locations, I think one was in Georgia).