According to https://www.odoo.com/odoo-12-release-notes#part_8
Compute the cost of products based on their BoM in mass directly from the product list view.
I have set my category costing method to FIFO and Automated Evaluation. After producing a Products it's stock value is just taken from the "Cost" field instead of the BoM. And if the Cost is 0 the MO is stuck with the message:
The cost of ... is currently equal to 0. Change the cost or the configuration of your product to avoid an incorrect valuation.