RE: Prop nut torque specs?
I think you should contact the manufacturer of the propeller.
17 foot/pounds with a 3/8 X 24 nut would crush a zinger wood prop to splinters.
It would probably deform a master plastic and would probably be fine with a carbon.
But W8ye is right, you either have a bearing problem or deformed the prop flange to the point that it hits the case.