Almost no states finish counting by midnight on election night. The TV networks make calls, and mostly the winner is clear. But every single state continues to count votes beyond midnight on election day, and most states continue to count votes for days or even weeks after election day. As long as a vote was legally CAST on or before election day, it doesn’t matter if it takes until after midnight to count it. The only vote count that matters is the one certified by the state, not the count at 2359 on election day.
As far as ballots that are spoiled, late, missing postmarks, mismatched signatures, or any other fraudulently or illegally cast ballots, those should clearly be rejected. But that has nothing to do with Foster V Love.
Counting votes is different than Voting. An Election is the voting process. That must occur on 1st Tuesday of November per constitution. Therefor all late ballots are null and void because the votes did not arrive by specified Tuesday.