Email sent to an unsubscribed contact

Hello everyone!

I use the Mautic platform to sent newsletters. I have created a campaign that filters the contacts. If a contact has unsubscribed, then the campaign doesn’t do anything. If they haven’t, it sends them a transactional email.
Today though, an email was sent at unsubscribed contacts. What could the problem be?

I want to emphasize that the action of sending the email, is AFTER the filtering.

Thanks
E