Username returning null value for Termination less than SYSDATE in alerts notification.

Summary:

We are having an issue where we are creating a custom Termination Alert using Workers REST resource, and using the below filter criteria to fetch Terminations happened as of SYSDATE and less than SYSDATE, in the Alert template we are using the below expression to fetch the username of the terminated employee, but it's fetching username of the employee terminated as of sys date only (as of which alert runs), but returning null value for termination which are effective less than the sysdate as of which alert runs. For example if Alert runs as of today and employee is terminated