We strongly recommend that you cancel the whole process like Cancel GRN, Cancel PO line item and then recreate new line in the same PO with item category and ensure the components are fine in the purchase order and then perform transfer posting to vendor and then receive the Parent material through MIGO.
The process ensures that the components are tracked at subcontractor end and consumed correctly at the time of parent receipt. You will then have the proper accounting as well valuation.
The work around solution would be activating Vendor field for the Mvt type 201 from OMJJ and then perform goods issue to Vendor thorugh MB1A 201 Mvt type and you need to perform MR22 later to increase the inventory value.