[PBenz]

In my case, the script thinks that the sender of the message is not me, even though the email in Sent Items is definitely from me. You can see the log message in the Console app. It thinks the email is from somebody else:

9/13/12 8:02:46.938 AM OmniFocus[5624]: OmniFocus Mail Rule: Received message from unauthorized sender <incorrect email address here> - ignoring message

I sent another test from a different email account, and it worked. And then I sent a 3rd test from the original account, and now that worked too! Weird.

There is a clue, though: the person associated with the incorrect email address sent me an email about 20 minutes before I sent the email to OF. It was sitting in my inbox unread. I can't seem to reproduce the problem, though.