I stand corrected, I just watched the vid again, and they do have one side stopping to turn. I was going on what stood out to me on first watching and haven't been able to watch it again due to data limitation.
Thanks to youtube's 0.25 speed playback, on the very first demonstration of the bug, you can see that the first and third legs on the side are synced, middle leg is the alternate. Could be as simple as fixed gears to make the legs do a leap froggy one after the other deal.