Thanks for reaching out. Have you tried clearing the browser's cache & cookies to see if that fixes the issue? Here's how: https://goo.gl/e2dYZt . Also, try using a different browser or Incognito mode to check if that makes any difference.
Appreciate all the details. Please send a feedback report directly from YouTube with these steps: https://goo.gl/WdI0BK . While you may not get a direct response, we do review everything and use the details to investigate and fix issues. Thanks.