"notifications.events.addAttachment" appears in the Notification list when following a user

Preconditions: Create 2 new users without any notifications ON.
Steps to reproduce:

1. Log in as a simple user eg. U1
2. Go to User index > click on a user eg. U2
3. Under Notifications select "Following"
4. Log in as U2
5. Create some pages and add attachments to them
6. Log in as U1
7. Observe the Notifications

Expected results: The notifications UI appear properly.

Actual results: It appears like the notification for adding an attachment has no translations, or the UI is not ok.