Since you've implemented email into your app, it's time to start asking for email features.
I was confused as to why an invite I'd already accepted on the Messages page was still showing up as needing attention. It's because RW doesn't mark Messages as read when you read them. Please add a setting that marks Messages as read automatically. ("When you accept/decline an invite" and "immediately when displayed/when displayed for (x) seconds" are good starting places.)