Yikes! Try uninstalling and reinstalling the app updates to check if there's any difference. Also, switching network from mobile data to WiFi and vice-versa can sometimes do the trick. Keep us posted.
Hmm, as a next step, please send a feedback report directly from YouTube with these steps: https://goo.gl/WdI0BK . While every individual report may not get a direct response, we do review everything and use the details to investigate and fix issues. Thanks!