Absence approval notification not created when worker (employee) does not have a user account

Summary:

Has anyone encountered the same in Absence where the approval notification is not created for a worker (the person the absence is being applied for) does not have a user account?

Content (please ensure you mask any confidential information):

A line manager submitted a leave on behalf of his direct report. While the approval status of this leave is “Awaiting Approval,” it did not trigger a workflow notification. In addition, the transaction is not available on both Transaction Console and BPM Worklist.

Investigating this, we found out that the worker does not have a user account. When we added one and resubmitted the leave, the transaction finally appeared on both Transaction Console and BPM Worklist. In addition, it also triggered an approval notification.