Just don't mess with the volume or quality controls or anything-I've found that messing with the vid controls makes the problem more likely to show up. Sometimes it takes a couple of tries, but it usually works. So far the only fix I've encountered is to click on the track bar to skip backwards a few seconds, and then the video will play normally. If you find an answer for this issue, please let me know. I tried switching from Edge to Chrome, and no dice. I tried clearing my cache and browser data, but that didn't work. It's not consistent, either (sometimes it works fine and sometimes the rapid speed up with unchanging audio followed by buffering will show up out of nowhere), which makes getting screenshots or whatever a complete pain in the ass. A UCLA professor bet 10,000 that the video was wrong, saying it.
I've only seen it happen over the past two or three weeks or so, so I dunno what's causing it. A popular YouTuber filmed himself driving a wind-powered vehicle downwind faster than the wind itself. Any site I've gone on that has a built-in video player has occasionally had this problem, and I don't know why (which leads me to think that this might not be a Google-specific thing).
FINALLY, I found someone encountering the same problem as me! I've discovered it's not just YouTube, either.