Period End Receipt Accrual of Expenses with Encumbrance Accounting

We are using version 12.1.3 of Purchasing, Inventory, AP, GL, and Cost Management.  We have enabled encumbrance accounting for Purchase Orders only.  Our situation is that we have a large back log of AP invoices.  In Period1 we have Period End Receipt Accruals of $1000.  The Invoices, associated with the Period1 receipts, were not matched to the Purchase Orders in Period2.  At the end of Period2 the Period End Receipt Accruals do not include the $1000 from Period1.  Does this make sense?  In Period2, the accrual will only include receipts from that period????