In the hearing today, they showed how the non-authorized ballot paper was too thin and the sharpie ink blead through. This creates an error and thus a reason for a human to adjudicate the ballot, i.e. slide the vote from Trump to Biden. Of course, the ballot was designed so that if a bleed through occurred it could create a double vote and the adjudicator could choose which candidate the voter intended to vote for. That is my recollection at least. Could be misremembering a bit.