Advance payment residual amount negative when credit notes are reconciled

[yaazkal]

Module

Sale Advance Payment (sale_advance_payment)

Describe the bug

When a sale has a credit note, and that credit note is paid, then the residual amount becomes negative.

To Reproduce

Affected versions: 15.0, 16.0 but maybe others too.

Steps to reproduce the behavior:

One scenario: Sale order wants to be cancelled but an invoice has already been published, when the credit not is created and reconciled with the invoice the residual amount becomes negative

1. Create a sale
2. Create invoice of the sale.
3. Create credit note for the invoice

Residual amount negative:

Second scenario: The client wants to return products of the sale so a credit note is created and money is returned to the client.

1. Create a sale.
2. Deliver 2 products.
3. Create invoice.
4. Return 1 product.
5. Create credit note for 1 product.
6. Pay credit note with a payment.

Residual amount negative:

Expected behavior
For the first scenario the residual amount should 320 and not -320, for the second scenario the residual amount should be 320 and not -320 un less the user change the quantity to 1 product in the sale order where should be then zero that residual amount.

Additional context
This was tested on runboat.