I have the same problem. It is frustrating because I forget whether or not I have clicked the like button. Initially I thought that, because the like button was filled in, that all my watched videos would automatically have a “like”, but that is not the case as you still have to press the button. And now my dislike button has suddenly been filled in as well. There seems to be no solution to fix this, as I reset the app on my tv, and nothing changed! I have to double check with the YouTube app on my phone to recall whether I have pressed the like button on the video! YouTube should fix this issue but there is no way to get their help.
