Strange thing, that need to be explained in details.
There are two users groups:
Registered - ordinary users, which comments always have to be moderated. But, these users can also create Joomla! articles, which can be commented.
Redactors - moderators of comments, children group of Manager group (same as Administrators)
There are two users from Registered groups:
Notification system settings:
- notify (only) group Redactors when New (comment is) pending
- notify Content Author is On
The problem is with notification system.
1. When Mister X comments on the article he is the author of, everything is OK - (only) Redactors receive moderation e-mail.
2. But when Mister X comments on the article written by Mister Y, both Redactors AND Mister Y receive moderation e-mails, while Registered group have no any moderation ACL rights and it is not set to receive any notifications.
When I switch Off notify Content Author setting, in both described above cases, no one receives any notifications - neither Redactors (this is bad) nor author (this is OK).