The video portion of some YouTube videos freezes while the audio channel continues. I can advance the video using the slider, and the video will then play a few frames before it locks up again. Ths only happens with some videos, and there is nothing identifiable about those videos to differentiate them from videos that will play normally.

Initially, this problem appeared only if I right-clicked on a video to play it in a new tab, but now it seems to periodically happen regardless of which window.