I belive I have found a bug in regards to stockpile, or importing not sure which, I have my manufacturing slot set to local import only, and my stockpile slots to prefer local since I am manufacturing the part but just want to have an option to import externally if I cant keep up for whatever reason. Anyway as you can see in the screenshot I clearly have wing mirrors in the stockpile, and in the manufacturing bay but it is still importing them from external direct to the manufacturing slot, even though its set as local only. this is causing a large delay with production.
Attached is screenshot and save game.
2nd factory.xml (4.4 MB)