Mapping Mapwthdefault at tiem level -Values Missing in Queue context

Here is the logic

If (E1EDP19-IDTNR_EXTR is not empty and (E1EDP19-QULF)=001

map IDT_EXTR to target Buyerpart

else

    if E1EDP19-IDTNR is empty and E1EDP19-QULF=002

  if E1EDP01-MENEE IS NOT EQAUL TO AU

  map const (SEE_DESCRIPTION) to target

All context set to EDP01

Target is mandatroy field

1) data : If the 1st item level has the value IDTNR_EXTR and 2nd item level is not .

In the else condition also QUALF is not matching to 002 so not getting the value for else condition in second item level  .

So getting the error ItemDetail[2]/ns0:BuyerPartNumber. Values missing in queue context

How can we add mapwithdefault to not to fail for mandatory field

2 data I added mapwithdefault befoe else it worked for this data but failed for other test with 3 line items IDTNR_EXTR  values. 2nd line item was getting in target which is not

Thanks for your help