Used Zammad version: 3.0.x
Operating system: Linux openSuSE 15.0
Browser + version: Microsoft Edge (Canary), Chrome, Firefox, Opera, IE
When answering a ticket via mail the recipient should be the one, who created the ticket (customer).
When answering a ticket (or a response of a ticket), the recipient is always the one who is in the ‘to‘ field of the mail of the created ticket.
e.g.: Forwarding an email as a customer (firstname.lastname@example.org) to the ticket e-mail address creates a ticket. The recipient is email@example.com. Now, when answering that ticket via mail in Zammad the recipient of that email should be firstname.lastname@example.org but instead Zammad uses the ticket email email@example.com.
This issue only occurs (how it seems) on a specific ticket creator mail, which has the same permissions as all the other accounts (agent) and is also setup the same as the others.
Steps to reproduce the behavior:
Forwarding an email to the ticket mail and replying on that ticket directly in Zammad.