I've just bought new Lenovo k6 and everything is fine but I found this problem with YouTube videos. The sound isn't matching the video. There's difference like half a second but it's very disturbing. Can anybody help? Thank you in advance.
Are you using the YouTube app or the mobile site on your browser? If the latter, try using the app. If it's happening on the app, try going to Settings>Apps, select YouTube, then Storage, and Clear Cache/Clear Data, and Force Stop. Now open it again and see if the problem persists.
If the problem recurs in normal mode, you may have to start uninstalling apps one by one until the problem goes away. Unfortunately, there isn't an easier way to pinpoint the culprit, unless other people have experienced the same issue and can give you a hint.