Purchase order's CO (edit RDD or PDD) updating the Last_updated fields of other lines

purchase order’s CO (edit RDD or PDD) of an actual line not updating the Last_Updated field of that line but for other lines?. We checked in the PO_Lines_All and PO_Line_locations_All tables.

Oracle replied,This is an expected/seeded functionality that once the PO gets revised means change order triggered the PO_lines_all will take the last update date as Change Order date.