Dupe Motion Sensor not working at Granulator - LU-352881

That's because technically the dupe is standing at the cell with the logic port. He may move to the side as part of the work animation, but from a game mechanic point of view, he is standing at the center. Pressure plate sensors suffers from the same issue.

You can encounter this with the oil refinery as well.

IT seems it is because the dupe's position during operation is actually seen by the game at the middle block (two left of where model appears).    The dupe also does not relieve 'lit workspace ' when their displayed model is in light.