Re: shaft turns in neutral?
I too have seen the same thing with my 19' runabout, but I have not seen it with my 34' trawler yet.
But, on the professional side of the spectrum, I have seen clutches, PTO's, transmissions, etc. do this as well on industrial equipment. Never a problem. My backhoe does the same thing when you set the outriggers. As soon as those tires come off of the ground, they start to slowly spin without any sort of power behind them, and this is a hell of a lot more mass to start moving than a shaft and wheel. As Bond-o said, all due to oil dragging in the gear.