with our customized Version of Odoo-CE we have (after upgrading from odoo 11 to odoo 12) now the problem that changing the Produkt Image of a Variant overwrites the Image of the Product-Template.

we checked all references to any "image" variable in our customizations but there are no code-sequences that do anything about images.

do you have any ideas how/where i can debug to check why this ist overwritten?

It does not create the ir_attachment entry with name = "image variant" and res_module = "product_product". insteat it only changes/creates entries for res_module = "product_template", also if i change the Image of the variant.