Impact of enabling Generate system username when generation rule fails.

Summary:

When a new pending worker was created the checklist should be allocated and an email should trigger to their personal email. But the email was not being triggered to the personal email. So as a work around I have enabled the Generate system username when generation rule fails in security console. Email is now being triggered to the personal email. But due to the workaround will it creates any duplicate user accounts.

Please let me know any impact of this change.