debug from process_halted:

$_SESSION[d_r] and $_SESSION[process_name] will be NULLed after this report

    _SESSION["d_r"] => Array
        (
            _SESSION["vchrs_cashback_form"] => voucher
            _SESSION["amount_tendered_is_editable"] => 1
            _SESSION["overpayment_allowed"] => 1
            _SESSION["underpayment_allowed"] => 1
            _SESSION["voucher_num_allowed"] => 99
        )