Hi black feather;
Welcome to the forum.
I'm not familiar with this model. The microswitch that stops the rotation of the motor looks a lot different from mine. But this is what I'm observing. At the start of the cycle the motor arm is in the correct position. As the motor completes it's first rotation, there is a distinct click. That is the end of the motor arm glancing off the bottom of what I believe is part of the microswitch housing. So for some reason, the end of the arm dropped a hair, at the beginning of the cycle. On the second rotation, the arm has dropped even further, and what causes the motor to stop is that the end or the arm strikes bottom of the switch, and cannot travel any further. Also it does not stop in the correct position.
The first problem is that the arm shouldn't have dropped. Second, it should only make one full turn per cycle, then reset. Your third problem is that on the second rotation, when the arm hit the bottom of the microswitch, it should have reversed rotation when it met that resistance. Do one more test, and if the motor stops because it is hitting the bottom of the switch, push the button and see if the motor will reverse, and end up in the correct position.
Check the guide rails that guide the bisquettes to the burner. If you see any wear, you rails need to be adjusted. If you see any wear, I find the instructions on how to align them. Also check to make sure there are not obstructions that could interfere with the motor, and that there is no debris build up on the assembly that the bisquettes slide on.