Trying to update payment terms in a purchase order with one voucher already created

Hi All,

We are using JDE 9.1

In an issue reported , a business user has created a non stock PO and already created a voucher for it.

Now , he is trying to update the payment terms in PO header so that he can create another voucher with new payment terms.

But , the payment terms is getting updated in PO header F4301 only but not in F4311 PO detail.

Please advise if this is expected behavior of JDE system

Thanks in advance