Order date & order signed by AO are different.

Sir,
our client received a penalty notice us 272A(1)(d). Reply to that notice is submitted after the due date i.e. on 8th September 2023. On 9th september AO passed the order without considering our reply. AO mentioned in its order that the assessee did not reply to the penalty notice. Interestingly AO mentioned the date of order as 5th September but the order was digitally signed by the assessment unit of the income tax department on 9th September. Is this the valid order ? can we file an appeal against such an order ?