Deviation between the inbound and outbound intercompany postings
Possible reasons for deviations between inbound and outbound intercompany postings
The transaction is not booked in both companies' GL.
The transaction is booked in different periods.
Some of the supplier invoices and sales invoices are still in Status 1 in one of the companies.
Some of the credit notes and payment documents are still in Status 1 in one of the companies.
Compare the postings accounts payable for one company vs. accounts receivable in the other company. If you do not have access to the other company's GL, contact their accounting responsible to reconcile the deviations.