Visual problem with Jump Lists

[Caracarn]

I've been experimenting with color settings to achieve unity across Windows.
Meaning: the same color and acrylic effect everywhere.

I actually succeeded in that, except for a strange visual effect in the jump lists.
In this short recording you can see exactly what I mean.

glitch.mp4

Below are two images from that video that show the problem even clearer.
Shortly before disappearing/fading out, the background turns blue and becomes transparent.
It's just for a split second, but visually annoying nonetheless.

In the NC Styler mod I use this -

Target: Border#JumpListRestyledAcrylic
Styles: Background:=<AcrylicBrush TintOpacity="0.3" TintColor="{ThemeResource SystemAccentColorDark3}" TintLuminosityOpacity="0.6" Opacity="1" FallbackColor="#70283550"/>

If I remove this from the Control Styles, the fade out effect is flawless.

Is there a target that I need for the 'fade out' animation? Or am I doing something wrong?

Please keep in mind that I have zero experience with all this. I'm still in the process of experimenting and observing what happens.