Email address not always filled out

Infos:

  • Used Zammad version: 6.3 (but also in 6.2)
  • Used Zammad installation type: Package
  • Operating system: Debian 12
  • Browser + version: Any

Expected behavior:

  • When you click on ‘reply’ on an article, a new email message is made. In the TO-field, the address of the recipient should be filled out
    (of course this only works when the original message has been sent via email)

Actual behavior:

  • For some senders, their email address is not filled out. I have to manually enter their name (Zammad’s autocomplete works fine, so I don’t have to remember their email address) in the TO-field

I have this for at least two senders. These two senders are also collegues and are also agents, but they send their email the normal way to a support-mail address. When they are clients/customers, they really act like customers as well, I suppose. Their email address is filled out properly in their Zammad-contact as well. So I don’t really see a reason why the TO-field would be empty when replying to them.
This is a new installation of Zammad. I have used Zammed for years at my previous job and had things set-up quite similarly and never experienced anything like this.

Steps to reproduce the behavior:

  • Open a ticket that has been sent via email
  • Click ‘reply’ to write a reply
  • See that ‘TO’ is empty
    See screen shots below