The Biden-only ballots could be explained by the enormous hurry the fraudsters were under.

You know when you have to mail multiple sheets of paper to a company and the instructions say please don't staple or clip the papers together? That's because it takes the processing department a few seconds to remove a staple or clip. Why is that a problem? When you have to process thousands of letters a day, those few seconds per letter really add up.

Filling out the downballot would have taken just a few seconds, but they may not have been able to spare the time, especially if they were in a situation where they needed to "find" way more votes than they had expected.