Unable to create an internal shipment using cost price per warehouse
There is validation in the code of the product_cost_warehouse to ensure that all movements between internal locations use the traffic location. A move between internal locations cannot be saved without going through the transit location
https://hg.tryton.org/modules/product_cost_warehouse/file/tip/stock.py#l61
When an internal delivery note is created, Tryton needs to save the log to include the transit location in the movements. The problem is that Tryton cannot save the first move as it does not pass the commented validation.