Not sure if intended, but could be a bug. I'm not entirely sure what the hide feature is for, I suppose for elements that won't fade or something? In that case it's probably fine. Thought I'd report.

This is intended, all elements of the UI are faded out. Immersion provides it's own features for fading the UI if you would like to fade everything except for the Immersion frames.

Alright thanks for letting me know :)