Some families above the Cut Plane display in a view but others do not.
When an element is located above the View Range > Cut Plane but falls below the Top Plane, the element will determine whether it is visible or not.
For component families this is determined by the family category. The following component family categories will appear in the view even when above the cut plane:
For example, you have a Generic Model family that is above the cut plane but falls below the top plane similar to the image below:
The Generic Model family will appear in the floor plan view. If the family category is changed > Lighting Fixtures, for example, the family will not be visible in the floor plan view:
When troubleshooting a view first check the family category to see if it is one of the above 4 categories. If there is a scenario where the family needs to display above the cut plane you can change the family to one of these categories.
In a related issue, Steve Stafford had a great post on another approach a while back. I’ve included the Revit OpEd post here.