I didn't get an update, and it would be very strange for them to push something out on a Sunday, especially over a long weekend. I'd bet that your Xbox 360 hard drive cache cleared out and it was just redownloading the last update.
I think there is something to what you are saying because, it updates everytime after I play an original xbox game (SW battlefronts) which also needs ro d/l an update everytime I run it.