I tried to reproduce this, without any success.
I suspect that you copied the variable combination above from somewhere else within the Browser.
What makes me believe this is that it’s showing “blueish”, so as a link.
Please copy paste this via a notepad (run as is enough as well) to ensure you don’t copy any HTML content.
I think it is possible, that there is a conflict with Microsoft (or Outlook). I had problems with the sharp-sign (#) at the filesystem some months ago. Maybe its hard for Microsoft to resolve links with a sharp in it.
Is it possible to create a link without sharp? Only to test it…
[root@dre-ts-01 ~]# zammad run rails r "p Signature.find_by(name:'default (CSR)').body"
"<div>\n<p>Solltest\ndu noch Fragen zum Verlauf haben, klicke auf den folgenden Link:</p>\n<p><a href=\"#%7Bconfig.http_type%7D://#%7Bconfig.fqdn%7D/#ticket/zoom/#%7Bticket.id%7D\"> \#{config.http_type}://\#{config.fqdn}/#ticket/zoom/\#{ticket.id}</a> <br></p>\n</div><div><br></div><div><br></div><div>Viele Grüße,<br>\n</div> \#{user.firstname} \#{user.lastname}<br><br>--<br> IT Support - *replaced*<br><span>*replaced*</span>\n<br> Email: helpdesk@*replaced*.com - Web: <a href=\"https://www.*replaced*.com\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">https://www.*replaced*.com</a>\n<br>--"
I now copied the full signature into the Windows-Editor (without format) and copied it back…
The result is this one:
"<div>Solltest du noch Fragen zum Verlauf haben, klicke auf den folgenden Link:</div><div> \#{config.http_type}://\#{config.fqdn}/#ticket/zoom/\#{<a href=\"http://ticket.id\" title=\"http://ticket.id\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">ticket.id</a>}</div><div><br></div><div>Viele Grüße,</div><div>\#{user.firstname} \#{user.lastname}</div><div><br></div><div>--</div><div>IT Support - *replaced*</div><div>*replaced*</div><div>Email: helpdesk*replaced*.com - Web: <a href=\"https://www.*replaced*.com\" title=\"https://www.*replaced*.com\" rel=\"nofollow noreferrer noopener\" target=\"_blank\">https://www.*replaced*.com</a>\n</div><div>--</div>"
well there’s your problem.
Looks like it has been copied and destroyed by that.
Well, anyway - copy the following into a notepad and then into Zammad (to ensure we don’t transport any HTML stuff). Also ensure to replace your stuff in the notepad.
Solltest du noch Fragen zum Verlauf haben, klicke auf folgenden Link:
#{config.http_type}://#{config.fqdn}/#ticket/zoom/#{ticket.id}
Viele Grüße
#{user.firstname} #{user.lastname}
--
IT Support - *replaced*
*replaced*
Email: helpdesk@*replaced*.com - Web:https://www.*replaced*.com
You can then check the signature again, if it gets broken again, I’d be quite thrilled to learn how you break it.