Wheel weight corrosion

Hi was just wondering if anyone else has this problem? My car is 5 months old, has only done 4k miles, never been off road and is only washed with ph neutral shampoo but wheel weights are starting to look pretty rough. There is also a little corrosion on one or two of the locking wheel nuts. I had a BMW for 6 years on the original wheel weights and they looked like new. I intend talking to the dealer soon about it.

Will upload pics soon