Powered Risers - burn marked or?

[mgscs]

Hey! I just noticed one of my risers is starting to get a burning mark, should I be worried?

Bought from: www.hashstore.com

Picture of mark: https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-prn2/v/t34/1660390_10202861662081640_1269804845_n.jpg?oh=5eb74b2989ff3430b612942347188b19&oe=52F4A23A&__gda__=1391762092_e0d028aa6d169a02fb8ea0fc72632270

Picture of unused one: https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-prn1/v/t34/1618581_10202861755403973_1711090863_n.jpg?oh=38989cb25ed201a41cf56a1479c7efa0&oe=52F4A675&__gda__=1391748849_a99f17eb10a1647203ea7ea2c404da63


Setup:

4x Sapphire r9 280x - all powered
Asrock z87 Pro
intel something haswell
Corsair Ax1200i PSU
4gb corsair RAM.

What should I do? is shit still safe or should i quit?

[bitpop]

Looks ok you're pretty safe with that extra ground

[mgscs]

Thanks for the reply! Appreciated