Duplicate shipment keeps origin of stock move
When duplicate a shipment linked to a sale for example, the duplicated shipment is also linked to the sale via the origin of the stock moves. But adding more stock moves to the sale lines break the workflow of the sale as too much will be shipped. (Idem for purchase).
I think we should not copy the origin of the stock moves when the shipment is duplicated. But we still need to keep the origin when copying stock move as this is used for assignation, split etc.