What causes Costing to automatically create "Invoice variance clearing" transaction?

Summary:

We had recently cleared some accrual balances (caused by exchange rate variances) for old POs, using the Accrual Balance Adjustment feature in Receipt Accounting. Subsequently, for one of the POs, costing has automatically generated acquisition cost adjustment, and a fully costed cost transaction with transaction type: "Invoice variance clearing" with a past date (in 2023) as transaction date. Since we had not setup custom JERS for this event, or setup mappings in seeded mapping sets used by seeded JERS, this transaction failed in accounting.

Noticed that for this PO, there was a receipt return done AFTER invoice match. Attempts to replicate the same in TEST environment did not generate the Invoice Variance Clearing transaction.