From the GP teams comes a few scenarios where the Select Checks process does not pick up Invoices during the build process as this is a common issue we see in support.
— Read on community.dynamics.com/gp/b/dynamicsgp/posts/select-checks-scenarios-that-do-not-pick-up-invoices-to-be-paid
Select Checks scenarios that do not pick up Invoices to be paid. – Microsoft Dynamics GP Community
Payables & ReceivablesMicrosoft & the GP Ecosystem
Archived post from 2020. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.