The tolerances aren’t exactly the same from cassette to cassette. Make absolutely sure the lock ring is totally flat in the end of the freehub, it’s very easy to get a slight cross thread / lift up on one side of the lock ring. If that happens, you can’t tighten the lock ring down to 40Nm, and there will be a bit of wobble in the cassette. Clean the threads in the end of the freehub thoroughly, and grease the threads on the lock ring. Then apply even force with the palm of your hand, to locate the initial threads, and try and keep the tool level as you torque the ring up. If that doesn’t do the trick, you may need a spacer behind the largest sprocket, in the cassette.