Watched the video. It looked like the PTO was engaged,(you actually say that in the video) that is, the actuator (and control handle) were pushed forward, as it would be when the mower deck would be running. In that position, you should not be able to move the pulley. The clutch fingers should not be loose in any case. If you pull the control handle back and latch it, the fiber button will push on the center PTO button, pressing the springs in and releasing the pulley so it can move independent from the engine.
If my observation is wrong wrt to the position of the actuator, I apologize. But that's what it looks like to me.
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