I've been having this issue semi-constantly ever since the site relaunched where a video will stop playing and act like it's over well before the actual end of the video.
It's been more common on longer videos like unprofessional fridays, and it happens at different time stamps (usually after the 1 hour mark).
It is super annoying because it forces me to load the video all over again to be able to resume from where it stopped.
Please someone look into it.
ps.: if it helps, I'm using Google Chrome on an iMac running OSX 10.8.2