Reminder emails like birthday, work anniversary are sent without the bench running

I have a development environment where I restore customer database to debug any issue they face. I have restored such a database couple of days back. There was a birthday falling on 5th of October, all of the customer employees received “two” birthday reminders for the employee. One from the customer’s sender email and one from my email address (I have set my email address as default sender).

So far so good… but the interesting part is that I did not start bench yesterday and today still the mail was sent from my development server. I verified it in email queue.

This has happened multiple times for work anniversaries as well that the mail was sent despite not starting bench on my development server on that day or the earlier!

Any help is appreciated for knowing why the emails are sent, even when the bench is not started