I am using Odoo 15 with an enterprise subscription to manage a Belgian Business. 

With the proper configuration Odoo can present QR codes to simplify payment handling.

I have some issue though. When I open a vendor bill and click the "Register Payment" button, the QR code is not generated in the proposed payment.

On the other hand, if I go via "Vendors->Payments" and create a new payment there with the same information for the same vendor, the QR code is generated.

What am I missing to make Odoo generate that QR code as well when using the "Register Payment" button on a vendor bill ? That workflow would be the most efficient and fault tolerant one so I really would like to get that working.

Note: this used to work in Odoo 13 (though it did exhibit another unrelated bug).

Note2: I'd add an image for clarification, but I don't have enough karma yet.