How do you keep face blush from fading?

As one of my oldest girl almost had the entirety of her face blush faded, I went and blushed her myself following some of the basic(?) guidelines: cleaned her face with water and very mild soap and pat dry it, then sealed the original faceup using MSC -uv cut and then proceeded to blush her cheeks using a Faber-Castell pastels and a brush. Then finished it all by applying 2x sealing layers.

The outcome was actually pretty good as I managed to keep the original look and beauty.

Thing is that after roughly four months in, I'm baffled the blush on her cheeks is 70% gone, don't know if it was something in the steps I followed, the pastels themselves or something else im totally missing. As a side note, I don't take my girls out and keep them away from direct sunlight, even installed uv blocking film on the windows to keep most of the harmful light out.

Is this normal and expected or what would you advise i do or use to keep it from happening?

Thanks in advance!

 

edit: these are the pastels used:

 

Edited February 4, 2023 by puxlavoix

That's odd. I'm not sure what would make them fade that fast.

Only thing I can think if to take a piece of paper, prep it like you did the face up and test the pastels on the paper. Seal it and wait to see if it fades under similar conditions. It might be something in the dyes used to make the pigments, but that's a long shot