What time and server are you referring to? If you mean the age of the NZB (i.e. the time it was uploaded to Usenet), then it being on the server for 5 hours does not mean that it is cached. If it downloaded slowly, it was not cached.
It never did mirror Giganews. It is a misconception that Giganews gets mirrored, it came from an ISP stating on their website that "SAIX now mirrors Giganews...". That is not true, SAIX/IS only gets their feed from Giganews.
Well to be precise, it's a TV show, the latest episode aired. It's usually cached and I downloaded the previous shows during the day.
I see, I always though they did mirror giganews. By feed, do you mean text or binaries?