Some of it probably has to do with the file itself not being clearly organized, some of it is probably how Figma selects groups.
Where I work, we started to mark the spaces with spacer elements, which look like boxes that have the number of pixels on them. It felt like a waste of time after using Zeplin, but it’s just much easier to see the measurements at a glance and doesn’t require the engineers to measure everything themselves. As a designer, it saves me time because I don’t have to answer as many questions or spend as much time on the design QA feedback loop.