Pro Site Signup Subject not replacing wildcards

In the Pro Site Settings area, I set my subject to "Thank you for upgrading SITENAME to the LEVEL level!"

I made a test transaction, and the confirmation email subject was exactly "Thank you for upgrading SITENAME to the LEVEL level!" Wildcards in the body were successfully replaced.

On the Settings Screen, from the position of the description of the wildcards, it appears that these can be used in both the subject and body.

Thanks.