However it stops in two different places in your video. So I doubt it's that.
I think it might be one of the linkages catching.
Instead of restarting it the way you are, try flicking the vane very gently. If it moves then it's not the vane and you need to look elsewhere.
You'll notice that the levers coming out of the back of the clock operate the three reel stops and the coin slide release, there are several linkages any of which might have a rough edge. That's where I'd be looking.