The form from your first day
You started a new job and signed a stack of paperwork. One of those pages may have been an authorization, and it can keep working long after the day you signed it. Requests can be answered from your payroll record without a fresh question to you, and you may not receive real-time notice of any single one.
Data is received from employers' payroll systems on a per-pay-period basis.
Source: The Work Number social service verification page.