Hi there, I just found the issue when you are using both Greg’s High Performance SEO and Subscribe2 that on confirmation page where you see the message "You have successfully subscribed!" or "You have successfully unsubscribed." these message will not show and instead the form will show up.
I tried changing setting of SEO plugin but so far the only way to fix is to disable the plugin entirely.
I have no clue how this could be fixed but if you can look into it I would be appreciated.