I've been working on getting some mbox importing scripts working, and I've found that if I import a message via lmtpinject, then delete it via the web UI, I can't reimport that message again.

I don't get any errors in the lmtpinject output, nor do I see anything in the logs about it being rejected or discarded. I've tried emptying the trash as well, in case it was doing some unique-detection on message-ID (which would be a little spooky in its own right, I must say).

If I restart Zimbra it clears up and I can reinject a given message, but that's a pretty invasive solution for iterating on these tools. Anyone know where I would poke to have it purge whatever cache or list is keeping the message from being re-injected?