Ever since the new design was rolled out I'm having a problem with buffering.
If I leave a video to load it will buffer forwards, though it doesn't come up with the light grey "buffered bar" that it used to have. I can click on a point in the dark grey "unbuffered bar" in front of the playhead and it will play, depending on if it's buffered that far in the video yet. I can't tell visually.
Also every time I click behind the playhead it will reload the video from the point I clicked, even though it's obviously been buffered because I was watching just a few moments ago. There is never any light grey being generated behind the playhead.
My only client side update was a Chrome update a few weeks ago before the new YouTube design, and it worked fine then. So I'm assuming it's a flaw in the new design. I'm running Chrome 15.0.874.121 m.