Hey there! I really appreciate the “new user of the month” award but one message & email would be enough 
Thanks for the report!
Backstage is powered by a third-party platform called Discourse, you might want to report this issue over at their community forum as a bug: https://meta.discourse.org/
That said, I disabled the New User of the Month badge so it should not spam anyone any more. Also, there are really powerful settings you can tweak on your Backstage account page, you can dial in what emails you want to get and how often.