SLA not working for integrated Supplier adjusted Cost

We have an integration where supplier invoice lines gets reversed from Project Costing and then consolidated into a single line. The original cost enters with the Transaction Source = Oracle Fusion Payables, but the reversal posts with Transaction Source = PLC Extension.

During accounting of the reversal, Subledger Accounting raises an error:

“Subledger Accounting couldn't retrieve a value for the accounting flexfield account rule. The GL account can’t be derived by account rule… Review the account rule definition and the extract source values… ensure a valid GL account can be derived.”

In the SLA setup, the account rule for supplier cost adjustments references the