Currently, when an anonymous user is talking (by mail) to a GLPI User (from the interface),
The anonymous user is having both notification from the GLPI User, and from himself. (Follow-up notification).
It would be good i think to have a way to avoid that, maybe by adding another option in the notification settings
Currently the follow-up notification have as event "New Follow-up", maybe a new event can be added, for example "New Follow-up (from GLPI user)"
In that way, we can avoid the anonymous user to receive both notification as said earlier, and we can even create some new custom notifications for them ! (E.G : Your answer has been received....)
Customer support service by UserEcho