I have discovered two methods to get rid of the stuck closed caption phrases that work for me!.
1) Uplug TV from the wall let it sit for a few seconds 15 or so then plug it back in.... the stuck captions are gone.
2) Using remote, Turn TV off for about 15 seconds.. no need to unplug. Turn TV on ..(don't worry about captions still there). Then Turn TV off again for about 15 seconds....... Turn TV on again.... This time you should see the Smart TV heading.. When the Smart TV heading clears the stuck captions will have also cleared!
The problem is the captions keep getting stuck on the screen! So for me, it's easier to turn the TV on and turn off as it takes about 30 seconds rather than unplugging the TV from the wall frequently!
I hope one of these methods works on your television!