Fulcrum wheel issue..

Hi there, I have recently noticed some indentations on my 11mth old Racing Zero 7s hub spline where cassette attaches, appears from cassette. I notice no performance issues,  noise etc from the rear wheel other than the fact I know of their presence. Wondering if anyone else has come accross this? Quite expensive wheels really and never seen this before so quite surprised. Both the retailer and Fulcrum answered my queires with the remarks that it happens and in no way detracts from the performance!! Torque the cassette down and it will be fine, which it is but I feel it should be replaced.   Thoughts. cheers