let's get the controller out of the picture. Disconnect it and jumper the out-gnd and thru-gnd with a piece of wire momentarily and see what happens.
After looking at the video again at 0:13, when it stops the first time, I am wondering if the rail tab just under the segment gear is rubbing.
Check that and perhaps flatten it at the bend with a flat blade screwdriver and a light rap with something small. Another screwdriver handle?
The other thing that I notice is the position of the motor gear. I looks like it's binding.
Loosen the motor mount screws and see it you can get any play towards the center of the bracket or change the angle slightly. I don't recall if the mount fixes it or not.
Everything should be loose with the motor off of the segment gear when you move it with your finger. When I tuned my used switches, I only tightened the screws to snug.
I came across one that was well used and a point was dragging. There was no fixing that.
