This is also happening to me. Even with compatibility mode turned on, the website doesn't work at all and constantly reloads every few seconds. In Safari or other browsers, there are no issues with it.
Because of the instant-reload, it might be something that happens during first load. Because it's Plex, it will connect to various servers of your friends & family that are shared with you. Maybe these connections are the issue? Anyway yeah, what the User "jist" showed above is how it looks for me.
