Originally Posted by
philefluxx
More than likely this is the case here. I am willing to bet though they found a bug in the bad luck protection that wasn't allowing it to trigger. Chances are it has something to do with x amount of completed tasks that could merit a legendary and a bunch of people went past the threshold, once the bug was fixed it probably went into recoup mode.
This would also explain the lack of documentation of any changes, Blizzard probably learned from the last shit fit the community threw regarding people getting a 2nd legendary if they had already got the first that it would be better to leave the fix unreported.