How to Identify Employees Who Made Benefit Elections During a Benefits Event?

Summary:

We have observed that when an employee makes a dependent change during a Benefits event, the Election Mandatory Date is updated to the current system date (SYSDATE). However, when no dependent/election changes are made, it remains as the last processing date. Is it event based?

We would like to confirm whether this is expected system behavior and understand the recommended workaround/reporting approach to identify employees who have processed/accessed the event.