For about the past week both East and West livestreams have been very hitchy for me, constantly switching between qualities when set to "Auto". I've been using the "Auto" setting for quite awhile since it usually provides the best quality (even more than "High") but something must've changed recently to make the setting very aggressive. I haven't tested other browsers, but this is happening to me on Firefox 65.0.2 (latest). This is on my gaming desktop on my gigabit fiber optic connection, so I don't believe PC or connection issues are the culprit.
EDIT: This is also happening on other qualities as well. I set the latest stream (Breaking Brad) to "High" and the stuttering / start & stop is happening there too.