Are you using Secure Folder? I don't believe this is the type of app that would work with Dual Messenger but are you using Dual Messenger?
Are you using any beta version apps?
Do you have multiple accounts with News Break?
If you turn off every other tick, does that result in only one notification?
Has it been this way since you got the app, or did it change?
Since this issue only appears to be affecting this one app, we'll start there. Let's clear the app cache. Settings>Applications>News Break>Force Stop>Storage>Clear Cache/Clear Data. Try the cache first and then check if the app still has duplicate categories. If clearing the cache doesn't do it, clear the app data. This will reset any settings that you may have changed from default, and will cause you to sign-in again if this app requires that. If neither of those get rid of the duplicate categories, I would try a fresh install. Uninstall the app completely and then install it again. If there was a patch or update that caused this sometimes a fresh install can correct bugs.
Let us know what you find and we'll offer more advice.