P0411SV saves different DDJ&DDNJ for vouchers in the same batch

Posted on behalf of customer:

In 9.1 / P0411SV Speed Voucher entry when creating a batch with multiple vouchers for different vendors with the same Payment term (006 - Due on receipt), the DDJ and DDNJ fields are not the same (ie: for some of them due date with +31 days) for all of the vouchers in the batch.
Same test in P0411 Standard Voucher Entry: all the vouchers have the same DDJ and DDNJ.