LightmapGI does not take custom ambient light into account

Godot Version

Godot 4.6

Question

I have a WorldEnvironment Node with a background color and a custom ambient light color:

When I bake the lighting using a LightmapGI it does not seem to take the custom ambient light color into account, it seems to still use the background.

Baked light with my settings:

Baked light with white background (what it should look like since my ambient light is white already):

Does anyone know if this is a bug or an intended feature?

And more importantly does anyone know how i can have a brighter ambient light without making my background lighter.
Thanks for the help!