Detail Views should obey plan region view range if detail crop region is fully within the plan region.
Here's a link to the discussion:
It appears that detail views (sections) cut in a plan view do not use the plan region they reside inside to determine if they are to be displayed or not. Their display is dictated solely by the view range of the main view. All of the other model elements behave as expected inside a plan region in that they are displayed according to their geometry as cut by the view range of the plan region. Detail views / Sections don't do this.