Warehouse print is done with the users logon language in standard, would not make much sense to do it differently as it is a very local activity, you just have to deal with the employees who are working in your warehouse.
Printing a single TO in 2 languages would only make sense to me if you employed migrant workers who do not speak your language (but then you have certainly more problems in communication than just with TO print)
So this described effect might be caused by an own developed print program.