SRAM cassette loose on DTSWISS hub

There have been a few transmission cassettes with lateral runout.  I had one that had shifting issues and it was warrantied by sram through my LBS.  

Any chance the freehub body is XD-R, not XD? I have an mtb hub with XD-R body that requires a spacer.

There are a few things I'd look at if I were in this situation. One, I'd remove the cassette and put a tiny bit of grease on the freehub splines (if you haven't already) to be sure it's sliding all the way on smoothly. Two, I'd drip a little bit of low-viscosity lube around the edge of the cassette's integrated lockring -- sometimes on SRAM cassettes, that piece can be stiff or slightly binding within the rest of the cassette, and a little bit of lubrication can help it turn independently like it's supposed to. And three, once you're confident the cassette is fully seated and properly torqued, I'd try to determine if the "wobbling" is caused by play between the freehub body and hub shell, or by the cassette itself. Not sure from your description how you are feeling or observing the wobbling, or if it is lateral run-out like someone else mentioned.

I would definitely try clamping the hub in the frame like SRAM suggested. Even if it doesn't solve the problem it might help you rule out some possible variables. Hope this is helpful. 

I asked the SRAM rep about this, they recommended removing and reinstalling clocked 180 degrees opposite and seeing if that resolves the issue. I have spoken with SRAM tech support as well, they don't have a specific millimeter runout that triggers a warranty. Usually it only becomes an issue when combined with a derailleur that has sloppy pivots. 1mm is ok, when it gets to 2+ it is hard to get the shifting working, at least with GX AXS.