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: 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.
If there's any doubt about which message is triggering the rule, you could extend the logging a bit, perhaps something like this:
-- Allow the user to type in the full sender address in case our trimming logic doesn't handle the address they are using. set theSender to sender of theMessage set theSubject to subject of theMessage set theText to content of theMessage if (length of theText > 80) then set theText to text 1 through 80 of theText end if set trimmedSender to my trim_address(theSender) tell application "OmniFocus" set AllowedSender to allowed mail senders if AllowedSender does not contain trimmedSender and AllowedSender does not contain theSender then log "OmniFocus Mail Rule: Ignoring message from unauthorized sender " & trimmedSender & return & " Subject: " & theSubject & return & " Text: " & theText return end if end tell