Thank you for reporting this behavior to the Community, although I'm sorry to hear that you're experiencing an issue with notifications on the Simplifi Mobile App.
To clarify, is the issue just occurring on the Simplifi Mobile App? If so, what happens when navigating to the Achievements page directly on the Mobile App (without clicking on a notification)? Also, have you tried clicking on any other notifications to see if the issue is specific to just Achievements, by chance?
If the issue is just occurring on the Mobile App, I'd suggest first signing out and back in to see if doing so helps to clear things up. If the issue persists, I'd next recommend performing a full uninstall/reinstall of the App, while performing a device reboot in between.