Issue with idoc INVOI02

Hi All,

I have not worked with ABAP, more into functional area. I am presently working with IDOC INVOIC02. The problem is this idoc is successfully passing in SAP but for few idocs the field BELNR is missing under the segment E1EDK02.

it is not happening with every order, just for few orders. I am not understanding why this value is missing. The Qualifier used here is 009.

Can you please guide?

Regards,

Nisha