I read the instructions on https://support.freshdesk.com/support/solutions/articles/236380-reply-to-a-forward-should-open-a-ticket explaining how to let a ticket re-open in case somebody replies to a forwarded email.
However, this has the unwanted side effect that the ticket will also re-open when the agent himself adds an internal note. Any way around this?
The ticket is re-opened when a reply is sent because an Observer rule has been set up to do this. I have checked, but it is not possible to distinguish between a note raised by an agent and a note raised through a third party answering a forwarded email. So, I don't see a way around it.