Helps if we had:

Pics of the seat...
Colour of the seat...

Please also update your profile with vehicle details. Saves you having to repeat it for future enquiries

 

2 things will help everyone here trying to give you answers.

1. Click on Avatar, -->Account Settings, -->Vehicle Information. Complete that info so that it will appear every time you post. Will give everyone a level playing field when attempting to answer your questions.
2. Post photographs, if possible, of the areas in question. Get them as sharp & clear as you can.

Any knowledge of the previous history of this vehicle?

TDK got his advice in before me, but both of our advice should be followed.

 

??? Leather seats . . . only the faces of the seat (ass & back) are leather, the around edges (where?) are the fake leather panels.
If its discoloring at the seams / sewing lines . . . . sun, cleaner or bad thread.
Did prior owner have aftermarket seat covers on ?

I don't even think FULL real leather seats can be had for under $100K anymore. My BMW didn't have full leather and it wasn't a base model

 

Thanks for the tip! My last ride was 70k and not all leather. My Honda salesman told me the CRV was all leather, lol

 

Personally, I think the time to have dealt with this was at the time of delivery In December, or at least just after you noticed this when you got home.

So, please post a picture or two so we have a better idea of what you are seeing.