About a year ago, I took my DB into Cartier to buy him a Love bracelet. He was trying to decide between a rose and a yellow. I have to tell you, they looked VERY close... until he wore them outside to see how they looked in the sunlight, and then you could see the distinction. Cartier's rose gold is VERY subtle compared to others, for example Tiffany's rose gold is VERY coppery looking...
Copper is a metal that can be affected by chemicals, and it can cause the rose gold to fade to gold's natural color, yellow. However, from what I have read on the forums, it has been highly variable. Some people, no issues. Some people, serious issues. Boggles my mind.
I remember listening to a woman that was trying to sell my DB a Rolex about how they have a new way of making rose gold so that it wouldn't fade. Of course, she didn't reveal what the alloy was that was keeping the rose gold looking rosy, but I am assuming platinum.
In the first pic, it looks like rose gold to me, and the second, not so much.
I would bring it in to your nearest Cartier shop as soon as you can, and compare for yourself how it looks next to a new rose gold...
I really think Cartier needs to address this issue...