The proposed workaround is: Following extensive investigation, the behavior is intended as design in the code below:TransactionReversal_Vend.reversal()if (isAdvanceReversal){ reversalDate = DateTimeUtil::getSystemDate(DateTimeUtil::getUserPreferredTimeZone());} In addition, following investigation, we can also reverse prepayment invoice by click on remove prepayment functionality on the purchase order form.The problem: Reversal date is the system date and not the invoice date or the session date. It would be better to follow the function of reversal of vendor transactions: to chose the reversal date. Otherwise I would have problems in my year end reports (balace sheet and profit and loss) if prepayment invoice posting date is different from reversal transation date!