Notifications re-appearing

For UNA app Android notifications will revert back to the amount when app was first opened when pressing back button on Android phones. For instance I open the app and it says 5 new notifications. I read 2 notifications then press the back button on my phone. The app instead of saying 3 new notifications it will convert back to 5 new notifications even though 2 have already been read and will stay like that until another task is completed. It's not a big issue because it does refresh just wanted to bring it up