Need to setup Invoice header DFF but facing issue due to interface line attribute values

Summary:

AR Invoice header DFF issue

Content (required):

we are using auto invoice to bring in transactions from external system through the FBDI template. We have setup Line transaction flexfield Context 'XYZ' and Attributes 1-9 and populated the template with Line Details including Attributes 1-9. At the same time our client needs to update a flag in the invoice header once the invoice is imported into AR, for which we had setup a Header DFF context 'XYZ' just with one segment mapped to Interface header attribute1. However after the invoice is imported when we query the invoice in RA CUSTOMER TRX ALL table, the interface header