DNS changes are often described as "propagating," but much of the delay comes from caching.
TTL (Time to Live) tells DNS resolvers how long a record may be cached before it should be requested again. A resolver that cached the old value can continue returning it until that cached TTL expires.
cPanel documentation notes that some DNS changes can take 48 hours or more to reach all nameservers/resolvers, and some DNSSEC transfer procedures advise allowing up to 72 hours for DS changes. Actual timing depends on TTLs, resolver behavior, and the type of change.
Changing a TTL after a record is already cached does not retroactively shorten caches that stored the previous TTL.
