Hiding an ornament in Immersive Space lets the real world shine through

I have a window with an ornament to the right. This works fine in the shared space, the ornament fades out nicely when being hidden. If I display the same window in an Immersive Space, however, a "cut-out" into the real world behind the Immersive Space appears once fading starts. This looks pretty weird. Is there a way to workaround this?

Another weird behavior: Windows and ornaments that have a glass background effect actually use the environment instead of the immersive space to apply the effect.

Maybe this is related to the fact that my Immersive Space shows a sphere with an inverted normal, i.e. I am standing inside that sphere, looking at an image?

Hiding an ornament in Immersive Space lets the real world shine through
 
 
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