Hmm, 'no-cache' meaning please cache it in reality may have been the problem in the past why those damn internet explorers cached ajax responses and the only way to solve it was to append a random query parameter?
It sends a revalidation request, so unlikely in theory, but probably many [shared] hosting providers set up a forced cache on server side ... or otherwise the server-side was wrong. (After all if someone used no-cache instead of no-store maybe they mucked up something else too.)
