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.
What technological gremlins haunt you?
Are you positive it was the exact same chatter and singing?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5567924/
ETA: white noise auditory hallucinations are common even in those without psychiatric disorders, even though that’s what the paper is based on, I just couldn’t find quick paper link about non-disordered hallucinations.