Don't reply to notifications via email
As with most websites, notifications are exactly that -- notifications. They are courtesy notifications to let you know that you need to return to the website to follow-up on them. Simply replying to notifications via email will only send the reply to me, not the intended recipient.
Replying to a notification in email could be a problem. One possible scenario: One evening over a beer, John tells Bob about a secret code that would allow anyone to walk into any bank and receive $1,000,000 one time without any obligation. So Bob sends a message to John here in the forum asking about that code. John replies to the notification via email, providing the secret code. Sorry Bob, Wendell's the one who will be rolling in those greenbacks.
Note also that the notifications instruct you not to reply to them by pointing out that you need to return to RPLS Today to respond. They even give you a link to click that takes you directly to the conversation so you can easily reply.