I've got a new Mavic Crossland front wheel with the CenterLock disc mount. I picked up a Shimano RT-53 160mm rotor, which (naturally!) fits nicely over the CenterLock splines. The lock ring threads in smoothly for the first turn or two, but then feels like it's hanging up. AFAI can tell, it's not misthreaded. The disc is still loose on the splines, so the lock ring needs to go in another turn or two. Is this normal -- I'm leery of forcing it? Do I perhaps need anti-seize or grease on the threads?

It could just be a burr from manufacturing. I'd try the grease/anti-seize and torque it to spec. If it's still wiggling then you have an issue to take up with warranty.

Thanks, a few dabs of antiseize did the trick! All torqued to spec now.