I'm importing invoices and their associated line items from a third-party legacy system and as such, I'm using the External ID when importing the Invoice and the associated Invoice Line Item.

However, no matter how I approach it, Odoo keeps ignoring the External Id belonging to the Invoice Line Item.

This means that when I re-import the Invoice Line Item, Odoo duplicates instead of updating the existing Line Item entry.

The strange thing is that I don't have this issue at all when importing Purchase Orders and their associated line items.

My import steps are as follows:

(a) Import the Invoice with no line items associated with it. (See file: invoice.csv http://dl.archwayproducts.com/downloads/odoo/invoices.csv)

(b) Import the Invoices line items associating them with the Invoice created in step (a) above. (See file: invoice_line_items.csv http://dl.archwayproducts.com/downloads/odoo/invoice_items.csv) )

But the issue is that each time I import invoice_line_items.csv, it create a new line item instead of updating the existing one.

It's as if the Invoice lines / External ID field is ignored and Odoo generates its own External Id when creating the record instead.

Is there any reason why this would be? Especially seeing that the very same procedure works perfectly when importing Purchase Orders and their associated line items.