I believe the section’s reaction to mouse is inconsistent.
If the entire section is visible on screen, it is highlighted on mouse hovering anywhere inside the section, and it is selected on mouse click.
If no section edge is visible on screen, it is not highlighted on mouse hover, and it is not selected on mouse click.
But if any edge of a section is visible on screen, it is not highlighted on hover, but it is selected on mouse click.
I’m so much used to clear the current selection by clicking on the whitespace, this is a second nature to me, and I do it without thinking.
The current section behavior makes me constantly check if the section got selected when my intent was to clear the selection.
Considering that every other selectable canvas object in Figma is highlighted before being selected, you can always tell if a mouse click is going to select that object. Section makes an exception here for no reason.