Opacity of element in element is not correct in IE and edge?

[LanderBeeuwsaert]

In edge:

see: https://blinding-torch-9765.firebaseapp.com/about
Scroll down so that the background becomes white.
Open DOM explorer.

If you look at:
app -> background -> div -> div .image-container: opacity is 0.1
app -> background -> div -> div .image-container -> img .image : opacity goes from 0 to 1 with animation.

because image-container has 0.1 opacity value, img should actually go between 0 and 0.1 with animation, correct? (but does not. See in chrome for reference)

Thanks for the library!

greetz