Double-clicking the section edge in Figma will automatically resize the section to fit the content with 80-px paddings. This is a pretty simple feature, although a huge time saver and a super-powerful thing for file organizing. But in FigJam this does not work.
I am not sure if this is a bug actually, but originally sections came from FigJam so I suppose it makes sense to expect that in FigJam they should work in a similar way.