Check the authoritative source
Query the name servers delegated for the domain and inspect the record type, value, and TTL there. If the authoritative response is already wrong, review the zone data and delegation rather than waiting for caches.
If the authoritative answer is correct, compare several recursive resolvers and note their TTLs. A resolver can continue serving a cached value until its remaining TTL expires; local network or browser caches may add another layer.
Narrow down the source
Check that the domain’s registrar delegation points to the intended name servers and that the queried hostname is spelled correctly. A stale delegation can send queries to a zone you are no longer editing.
Avoid repeatedly changing records while caches are expiring, since each change complicates the comparison. Record the tested resolver, timestamp, and answer so you can distinguish propagation from a persistent configuration issue.