[Closed] Play in deore cassette

Noticed this a few weeks ago when servicing my bike, doesn't appear to be a problem but is strange. If you take the cassette off you can grip the sprockets and they will turn fractionally realtively to each other. There's no side to side movement. I noticed that they are now riveted together and not bolted as previously and wonder if this has anything to do with it.

Using a steel freehub body so not concerned about wear and it doesn't seem to be affecting the shifting (crap as always ;)).

Do the lower end SRAM ones do this or are they a different construction?