In all cases of treasurers' deeds for lands sold by county treasurers for nonpayment of taxes, whether heretofore or hereafter made, the certificate of the prothonotary endorsed thereon, under the seal of the court, to the acknowledgment of such deed, or the record thereof when such deed shall have been recorded, shall be prima facie evidence of the fact of such acknowledgment: Provided, however, That such prima facie evidence may be rebutted by showing that such deed was not acknowledged, when the records of the court do not contain any entry of the acknowledgment of such deed; And provided further, That this act shall not affect any adjudicated case.