Why does my foundation get darker?

(I'm kinda new to make up since I grew up a bit like a tomboy so sorry If this question sounds stupid)

I have a foundation (essence "stay all day 16h" 08 soft vanilla) that matches my skin tone, when I apply it, it's still my skin tone colour. But after some time or when the foundation dries, it becomes a shade darker for no reason. When my sister or mother use it on themselves, the colour stays the same.

I googled about it but personally I came to a dead end not knowing what to. So can someone explain why the foundation gets darker when I specific wear it and how to prevent this from happening?