Route 53 answers DNS queries using hosted-zone records and routing policies. A DNS record points a name toward a destination; it doesn't start the application or grant access through a firewall. The TTL tells resolvers how long they may cache an answer, so a record edit need not appear immediately everywhere.
Caching can reduce repeated work and latency, but stale values and invalidation become part of correctness. A CDN cache for static content, an application cache for database lookups, and DNS caching operate at different layers. Health-aware routing can help steer traffic, yet the underlying endpoints still need capacity and a recovery plan. In the edge cases, a stale answer isn't evidence that a deployment failed, and a healthy DNS answer isn't proof of an authenticated application response.