That means it was shipped from inventory, not from the job. Might be helpful to look at the pack in Customer Shipment Entry and see if it shows shipped from inventory.
Even though a part is marked non-stock (i.e. made to ship), Epicor will let you ship from inventory. An example of where you would want this is you make more of the part than the original order requires (e.g. min mfg lot size or just ran more), you can put the extras in inventory and sell them later, shipping from inventory.
@Will79 - take a look at the methods for those parts where this part is a subcomponent and see if the operation is marked as backflush. There is a hierarchy of where Epicor gets the backflush warehouse and bin.