I'm glad I'm not the only one, this was giving me big problems, with Firefox on my mac

I'd click on a youtube video, nothing would happen, and I'd tab over to my CPU monitor (which I kept running for just this purpose.) and I'd see the load up around 230%. I'd have to kill the process and usually give up on the video. It would only happen to some videos, but consistently the same ones. And I'd definitely see a problem with the buttons below the video - seemed like when the tab locked up sometimes the far right button would be rendered beneath the column on the right, like the reflow failed.

I haven't seen it happen again in the last few days.