Hmm, have you tried checking on your internet connection, clearing your cache & cookies, and checking if this occurs on other browsers? More on those here: https://yt.be/help/qtVT . Hope it helps!
Sorry to hear you're still having trouble. We'd recommend sending a feedback report directly from YouTube, here's how: https://yt.be/help/feedback . Make sure to send from the account experiencing the issue!
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