Seems like a VRM. They can handle higher themps than let's say the GPU chip or the memory chips but they also get quite a bit hotter.
Those rarely have built in temperature sensors (you can check with GPU-Z) so I'd suggest that you pickup a cheap IR temp gun and measure their temperature full load. Note that they will be hotter in the middle.
It might surprise you how hot they can get especially if you overclock. If they are too hot I'd reseat the thermal pads or even buy some new, bit wider thermal pads (they're cheap) and replace them.
I used to have some Asus GTX 780 Ti cards which didn't gave thermal pads by default but had a temp sensor somewhere near the VRMs and they were reporting close to a 100°C if I remember correctly - while the core itself was 65°C.
So I picked up a couple of cheap thermal pads and put them in and the temps were back down to about 80°C .
The VRMs on this card do have temperature sensors and they are reading about 70C on both of them. the card is sitting at stock clocks now (1040Mhz).
Do you think it's a a bad sign? I don't want to open the card because there's a warranty voiding sticker on the back of the card.
70°C is nothing to worry about.
I think I got it though. Notice the discoloration only happens where the thermal pad makes contact. Some thermal pads have some sort of oily thermal fluid soaked into them. I think some of them got pushed out which caused the discoloration.
Here's a quick example of a similar situation:
These are non conductive so I wouldn't worry about it.
