We're in the process of migrating our users over to Zimbra. One of the users that we migrated was trying to setup a filter and ran into what I would consider a bug. He was trying to forward messages with a certain subject line to another user or group of users. When he filled in the "Forward to" box he made a mistake; he used the users full name instead of an email address. The filter dialog box allowed him to save the filter like this. OK, obviously the filter is not going to work, but beyond that by having this filter in place and activated he could no longer receive email. The /var/log/maillog and /opt/zimbra/mailbox.log showed entries like this:
Mar 8 10:41:27 email postfix/lmtp[22188]: 13C2B608795: to=<jwelch@brosco.com>, relay=email.brosco.com[], delay=0, status=bounced (host email.brosco.com[] said: 554 5.0.0 Permanent message delivery failure (in reply to end of DATA command))

2007-03-08 10:41:27,181 INFO [LmtpServer-66] [name=jwelch@brosco.com;] filter - redirecting to John Welch
com.zimbra.common.service.ServiceException: parse error: wrongly formatted address: John Welch
Users being users, especially new ones, they are bound to make mistakes. I think the system should either warn the user of a bad filter, or the filter should just not work. It shouldn't totally stop email from being delivered.

Am I missing something here?