UI Button and Color Tint Transition issue

Hey everyone,

I found a strange behaviour concerning UI Button color tint transition.
From what I understand, if I use a white color for my UI Image, the transition colors configured in the button should be exactly the same but this is not the case, they are over brighten especially if I try to have a dark color for the button.

Any idea if there's a way to correct this behaviour, is it a bug ?

Thanks a lot.

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