DMT for 10.1.400.18 JobMtl error

Receiving error importing JobMtl “Warehouse should be blank against the site where the Part was not set up.” We imported the Job Assemblies then tried importing the Job Material. When I look at the part in Epicor, the Site is MFGSYS which matches the import file. I’m not sure what this error is trying to tell me. Anyone seen this before?