zmpurgemessages leaving emails in inbox
I have users for which their email address should simply be an alias to another email address (not hosted in my zimbra server). Since aliases in zimbra can only forward to accounts on the same zimbra host, I created a "placeholder" class of service which I use for these accounts.
I've setup this class of service to clear everything after 1 day (Email, Trashed and Spam message lifetime settings are all set to 1 day). The problem is zmpurgemessages does not clear the inboxes after 1 day as the Email message lifetime setting says it should so all emails accumulates in these inboxes (people with these accounts will never log in Zimbra). I made a couple of tests and zmpurgemessages clear emails that are in the Trash and Spam folder ok but it does not clear the inbox!
Is that a bug or is it just me not understanding what the Email message lifetime setting is supposed to do? If it's the latter, how should I set up alias to external addresses that won't result in emails accumulating in inboxes?
(I'm using 4.0.3)