They might be legit votes. They might be fraudulent. No one knows. Should they be used to determine a winner?
Without a chain of custody they are ballots, pieces of paper, not votes. The real question is what do you do with a box of known legitimate votes mixed in with known illegitimate ones? Relative numbers are unknown. Count them or not? Either way you are disenfranchising some legitimate voters by not counting their votes or having them cancelled out by fraudulent ones. One solution would be: Do not count them. This would send a message to the electorate in that district to put competent and honest people into the office of election supervisor regardless of party label. If we lose confidence in the honesty of elections, it is a small step to "why bother".
Assuming it was a mistake fine the responsible officials. Let a jury determine whether it was intentional. Jail time if it was.
Because of judge picking, there is no jail time if there is not charges broughtt because of crooked ness and corruption
Back during the good old days when America was great, beer or liquor couldn't be sold when the polls were still open. You had to have a pretty good reason to ask for an absentee ballot, either you were going to be out of town or in your deathbed at some hospital. Most voter fraud occurs with absentee ballots. And when the polls closed it was armed local police or deputy sheriffs who picked up the locked ballot boxes at each president and transported the locked boxes to the County Registrar office to be counted.