I think the problem, or should I say, limitation here lies in the fact that the Floor Plan is a symbolic representation so there the transparent fill background can show what is behind it.
However, Sections are generated from the 3D model, so first the model is generated (in which phase, the program calculates that those line segments of the Curtain Wall view are not visible so it does not show them), and them the graphics of the elements are overridden.
Improvements could be made in displaying elements covered by other elements in 3D Viewpoints. You could make a wish for that in the Wish section. If you do, please post its link here.
Until then, I think your best bet is to draw those missing lines by hand in Section.
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