Wouldn't be much of a thing it was a random batch of ballots that was just missed.
If the votes were evenly distributed it would add equally to both candidates, with at most a 600-votes-edge for one candidate (allowing for a +/-5% variation).
Most unsurprisingly those last-minute batchhes always have a huge deviation from the statistical means, like 80%+ for Democrats. That's statistically impossible. Even if you lack the math: any decent gambler intuitively know this.