Greetings, I recently purchased a SRAM PG950 cassette for my shimano hub. The first 7 cogs are attached in a stack and the final two are free. They all fit on the hub (uniquely) however the second to last cog has a strange profile on the inner ring that allows for a significant amount of play on the freehub. When torqued down, everything feels solid but the profile seems very strange to me. Can anyone explain this?