I was finally able to track down what is causing some arena profiles to get out of date. A lot of armory requests were still failing but appearing to have succeeded. I have come up with a way to help guarantee that it should no longer happen. I am running a manual update as we speak, and hopefully in the future it will no longer have any issues.
This should also help keep the rankings page more accurate. I am updating now with the changes. In case you haven't seen it yet: http://www.arenajunkies.com/rankings/
After tonight, please report if it seems your profile goes out of date by more than a day. Thanks for your patience. I am sure we are all glad to see this finally resolved :)