Note: this is not a request for troubleshooting help.
For the past few years my 10ish year old “smart” TV will maybe once a week or so completely lose the ability to play sound in the Youtube app, and only in the Youtube app. Sound works just fine everywhere else. Bizarrely this is always triggered by an ad and never a video. Restarting the app doesn’t fix it, and neither does clearing the cache. Fortunately doing a full restart of the TV fixes it, it’s just irritating to have to restart because an ad somehow broke the sound.
My 9 year old LG smart TV (WebOS, but never connected to the network) will occasionally "overlay" RGB colour artifacts over the entire screen. There's no pattern of time, day, on duration, HDMI source, etc.
It just occasionally happens, probably once every month or two. Putting it into standby and back on again fixes it every time. 🤷🏻♂️