I FOUND THE ANSWER! Thanks to another Samsung board - get yourself a "toast source" app: https://play.google.com/store/apps/details?id=pl.revanmj.toastsource
Mine was also Badoo… I have deleted the app & am currently testing to see if an ininstall/reinstall makes it start again or not, so far, so good
@PT82 @brandonm71: Are you using a particular app or feature when you see the notification? Have you tried checking for any available updates via Settings > Software Update? If you restart the S9 in Safe Mode, does the issue persist? If not, please restart the phone and remove any recently installed third party applications, as this issue is likely to be stemming from an external source. To access Safe Mode, press and hold the Power button until the 'Power off' prompt appears on the screen then release > Touch and hold Power off until the 'Safe mode' prompt appears then release > To confirm, tap Safe mode > With Safe Mode enabled, ensure Airplane Mode is turned off.