Root Cause: Duplicate bills got created for one of the parts on the order.
Steps to resolve:
Check the BOM type model parts and see if there is any duplicates created in the apps.bom_bill_of_materials. If here are any duplicates then delete them and reprocess the order.
Below are the example queries:
select *from apps.bom_bill_of_materials
WHERE bill_sequence_id = ;
DELETE FROM apps.bom_bill_of_materials
WHERE bill_sequence_id = ;
Commit;