That is a judgement call. There are only 2 kinds -- judgement calls and those from the rulebook. It's the same as if a runner is thrown out at first by a step and the ump blows it. It was in his judgement that the batter was safe, therefore no out is recorded. An example of the other type is if one of the umps forgets about the infield fly rule and starts calling the wrong people safe and the wrong guy out. Historically, that call would have stood as it was his call to make. Like I said, I don't know what changed and why, but they're starting to overturn each other more frequently.