I have actually noticed that keywords for subject and bodies don't appear to be consistently available even though the items I am trying to use are actually available for other email replies/notifications.
Eg. I can't use %dept in the subject of a New email to a staff member. The subject doesn't appear to be available either.
I get many emails from different departments and was aiming for the ability to see the department the email was sent to without having the actually open the email.