Heres a comparison:
I didnt spot in instantly, and didnt expect something like this.
I was thinking what i accidentally change something in color theme, so i make a clear installation of 4.1.1 (with cleaning everything in AppData path), but problem are still there.
Is this a bug in UI?
I think it’s changed. 
4.1.0-alpha+main.d068407a004c
Shows the old behaviour there icons become darker.
In 4.1.1 (downloaded today from official site) - color stay unchanged.
I think its more look like a bug.
Try submitting a bug report.
If it is not the intended change, it will be modified.
Yup, already report it.
