Lacerte had a notice about this.  The portion of your overpayment from 2020 to 2021 may be split.  Part may show as an overpayment from 2020 to 2021 in the software with the remainder (portion paid on May 15th with extension) shown as an "other payment" in the software as this amount was paid after April 15th.  Therefore the portion shown as an overpayment will be the amounts that were paid by April 15th and any excess is shown as an "other payment"