Your seeds are all extremely close together. The System.Random PRNG takes a 32-bit seed, but your seeds haven't even got a 17-bit range, so you're supplying approximately 19 parts per million of the possible range of entropy. Evidently this PRNG doesn't fare well with such a small amount of entropy.

Try providing a broader range of seeds, and you'll see better results, e.g.
877554827
3377950428
3850407650
688135636
1134078904
973676998
3178940608
840705211
185598244