If you inactivate a user group that is assigned to an email notification, members of the group receive the notification even though the group is inactive.
Steps to Reproduce
Create an email notification.
For more information, see the product documentation topic Create an email notification.
In the Who will receive tab, click the Groups icon and add a group.
Navigate to User Administration > Groups, and select the group.
Set Active to false.
Trigger the notification.
Note that the email notification is sent even when the group is inactive (active = false.)
To avoid receiving notification on inactive groups, remove them from the email notification itself.
Related Problem: PRB670316