Purchase order not invoicing in Intercompany process


my customer is following intercompany process.

For example: he created original sales order which creates automatically purchase order company A and Intercompany sales order in company B.

when intercompany sales order posts invoice, automatically purchase order and original sales order of company A will post invoice. But here both sales orders are posted Invoice and status showing as Invoiced and purchase order is still showing as Received status. all settings I have checked and seems to be fine.

what might be the reason? Can someone help me.