@TeamYouTube Are there known issues with persistent code 400 errors and video pages that have been open but untouched for days at a time? I'm trying to track when it happens, but it's not consistent. Clearing cookies fixes it. What's the best way to send a detailed issue report?
Done. And the process helped me narrow down the cause of the problem, which, after further research, is an extension's fault and may be fixed in an updated version. So, uh. Never mind?