Who I have the same questioned this solution

You're welcome, best of luck! A hard reset could fix an issue like that if it was a software glitch or application conflict, because it would uninstall and re-install everything correctly. An indication of that issue being caused by a software glitch would be if it started happening soon after installing an android version update, and likely it would affect a lot of people with that phone and update, since it's not widespread that's unlikely. If it was an application conflict causing the issue an indication would be that the issue started after installing, using, or updating third party apps that have audio permissions. (Music, video, scanner, communication or function control apps). You can check if it might be an app conflict by running your phone in safe mode which will let you test the phone while only the stock apps are running to see if the issue still occurs.