I started to get a two-tone alert on TV with no indication about what it was for. It was really annoying.
Eventually found it was an alert on my Alexa App from Amazon shopping when an item is out for delivery!
Solved by opening Alexa App - settings - amazon shopping - notifications - turned off. No more alerts on TV.
Really don't know why Samsung help desk don't know about this as it seems to be causing a lot of frustration. Also if the Alexa notification flashed up on TV it would at least guide owners as to what the alert is for.