Pastel browning does this happen to all pastels?

Two years ago I bought a male and female pastel from a large national breeder. The male he said was maybe the best he produced that year the female was a throw in so to speak. Run of the mill slightly off yellow. We called her oldie goldie. He was brilliant yellow with nice full black markings. Well if there was such a thing as olive ball that's what I would call him. He's really darkened. My female has stayed the same as she was and has developed some blushing where I see a real diamond I the rough. Not to mention I also bought a lemon blast fora a diff source and it browned out a little but was very bright to begin with.
For reference my LB and female pastel color could compare to the color of a chicken leg( sorry for the example hope you can work with it).
My guess is a little browning is okay a lot sucks.

Love to see some comments.

I acquired a Queenbee w/Amir citrus. I hear it doesn't brown out. Is this true? I am going to keep these lines separate.

Not all pastels brown out completely, but they do all brown out to an extent.
Personally I like the blonde pastel line the most, especially in combo.

The more yellow/cream color the better, and just hope it stays with age.