Originally Posted by
FBinNY
Plus one here.
It is absolutely not normal, but the problem isn't the cassette or hub, it's you.
Freehubs depend on the lockring to compress the cassette against the back shoulder. For this to happen the cassette must overhang the front of the freehub body slightly. If the cassette doesn't overhang, the lockring bottoms out against the freehub body without touching then cassette itself. Your torque reading is simply that of the lockring against the freehub NOT THE CASSETTE.
Go back and add a spacer behind the cassette to bring it out, and all will be well.
On an 11T smallest cog cassette, the 'overhang' is little bit different. Since the 11T cog doesn't have grooves that extend fully through the cog, the 'overhang' that is needed is really a gap between the cutout of the cog and the end of the splines on the freehub body.
If the gap is too small, the lockring will cause the spline to bottom-out in the cog before it can reach and push/hold the rest of the cassette in place.
The OP didn't mention the freehub model but it must have longer splines than normal Shimano MTB freehubs.