Not sure if this is a bug or I'm just doing something wrong:
Since Zimbra 4.x doesn't support multiple accounts per session, I worked around this by having other accounts such as admin forward their mail to my primary mailbox. In order to separate mail from different accounts, I'm using filters such that any mail with firstname.lastname@example.org in the To: field gets put into its own folder.
This systems works pretty well for normal mail, the trouble occurs with spam. These filters are also applied to any mail in the Junk folder; in effect, hardly any spam remains in the Junk folder. The easy solution seems to be to add a *SPAM* prefix to the subject line of all suspected spam and add another filter to the bottom of the list that moves anything with *SPAM* in the subject line back into the Junk folder. Unfortunately, instead of moving the message to the Junk folder, it creates a copy in the Junk folder and leaves a copy in the admin folder.
Any ideas what's going wrong?