From the Dynamics GP Support Blog comes details on a Performance issue with the Received/Not Invoiced report in Purchase Order Processing
Performance issue with the Received/Not Invoiced report in Purchase Order Processing – Microsoft Dynamics GP Support Blog – Site Home – MSDN Blogs
Microsoft & the GP EcosystemSales, Purchasing & InventoryReporting & BI
Archived post from 2012. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.