Reminder reached mails should stop sending when a ticket is on state closed or is deleted
Actual behavior:
A ticket which was change to closed after it was on pending reminder still sends daily Mails “[Ticket #123456] Reminder reached …”. We decided to delete this single ticket to stop this, but we are very wondering that still we receive a daily notification.
Sounds like you have a second Zammad instance that happens to have the same ticket number.
As you didn’t clear the causing ticket (because other system) this probably is the reason.
Other than that: Delayed jobs.
If that’s not the case than it’s impossible to be triggered by Zammad.