No difference in forward and redirect on Zimbra

Question

We have the case, that we need to forward all incoming emails to a other email address in the same domain.

Here is what is happening with forward:

1. [email protected] receives a email from [email protected]
2. [email protected] forwards the email to [email protected]
3. The email should show from: [email protected] but still shows from: [email protected]

Here is what is happening with redirect:

1. [email protected] receives a email from [email protected]
2. [email protected] redirects the email to [email protected]
3. The email shows from: [email protected]

So the redirect works as intended, but the forward does not.

Can anyone tell me why Zimbra is not functioning as I am expecting?