A WebmasterWorld thread named News.Google.com problems? documented how when you did a search, for example on Reuters and then repeated the search over and over again, the number of stories, in a matter of a refresh, would jump from "26,900 to 13,500 to 0." Now I am trying this now, and I can not reproduce the issue. But others checked about 5pm (EST) yesterday, and have noticed the same issue. Maybe it has been fully resolved.
Forum discussion at WebmasterWorld.