Why resolvers answer differently
Every public resolver keeps its own copy of an answer and refreshes it only when the record TTL runs out. That is why, right after a change, some resolvers already return the new value while others still return the old one. It is caching, not a fault.
If a resolver still returns the old value well after the TTL has expired, the problem is usually in the zone itself: one of the authoritative name servers never received the updated version.
What this DNS propagation check shows
The query goes to six public resolvers at the same time, and the table holds what each of them answers right now, together with the TTL left on the cached entry. These are real queries made while you wait, not a world map with invented locations.