Subcontracting Components Not Consumed at GR

Plant or subcontracting controlling reports that finished goods have arrived from the vendor and the goods receipt is posted, but the stock at vendor for the components has not gone down, or has gone down by the wrong amount. Someone doing a stock reconciliation for the vendor notices the special stock quantity does not match what should have been consumed for the number of units produced. Sometimes it is finance flagging that a subcontracting cost account looks understated because no consumption ever hit it. Occasionally the report is the opposite: the components disappear from stock at vendor but no corresponding finished goods receipt exists yet, which points to a timing or sequence problem rather than a missing posting. Either way, the complaint arrives as a stock discrepancy, not as an error message, because the goods receipt itself usually completes without any warning.

Pull MB51 for the PO number across movement types 101 and 543 O and lay the two quantities side by side against the component list ratio from the PO. A 101 line with no matching 543 O line, or a 543 O quantity that does not scale with the 101 quantity by the BOM ratio, is the proof. Cross-check against MMBE for the component and vendor combination to confirm the special stock balance did not move on the goods receipt date.

If the component list on the PO was wrong or missing before the goods receipt, correct it on the PO item directly, a data change, then reverse and repost the goods receipt so the backflush picks up the corrected list. If the goods receipt already posted with a bad or absent component list, the only clean fix is to reverse the 101, correct the PO component list, and post the receipt again; editing the component tab after the fact does not retroactively fix a posting that already happened. If the root cause is the BOM component missing the subcontracting relevance flag or wrong alternative, that is a master data correction in the BOM, not a config transport, but it needs coordination with production planning since it affects manufacturing too. If the fixed-quantity indicator is the issue, setting it on future POs is a data-entry standard, not something fixed centrally; existing open POs with the wrong behavior need manual correction item by item. If components were never provided to the vendor, the fix is a process one: post the missing transfer to stock at vendor before the consumption can ever balance, and check why the transfer step was skipped upstream.

The common reflex is to post the missing component consumption manually with a direct movement against the vendor's special stock, bypassing the PO entirely. This makes the stock at vendor balance look correct again but it disconnects the consumption from the purchase order history and the goods receipt document. The PO's component list and its remaining open quantity no longer reconcile with what was actually consumed, any later cancellation of the original goods receipt cannot reverse the manually posted quantity, and the cost of the subcontracting operation gets misattributed. It hides the underlying BOM or PO configuration problem, which then repeats on the next order.

This sits with the MM or procurement functional consultant supporting subcontracting, working alongside production planning where the BOM component flag is the cause. The handover note should state the PO number, whether the 101 was already posted, the component list quantities expected versus consumed, and whether a reversal and repost is needed or whether the fix is a forward-only BOM correction.