Video desync after last update

Many videos on YouTube are having desync issues. The audio is unaffected, but the video will glitch and be out of sync with the audio for a variable amount of time. Seems fairly consistent as well.
To test, I downloaded the same video (https://www.youtube.com/watch?v=JYvIXD53lk4 - MP4, 480p) multiple times, and the glitches were the same every time. The first glitch is at 2:24 and lasts until 2:30 when it resyncs, the second occurs at 2:50 and lasts until 3:00. This is just one example, and I'm sure it can't be the video itself because I tried downloading with KeepVid.com and the result had no desync issues.