When Revit converts the IFC into a Revit file, it should translate all objects into Solid elements. But sometimes, for an unknown reason, Revit converts some elements to Meshes. 

This means that these objects don't have any data on the geometry that can be used.


Solution: Manual draw compartmentation boundary and check the height, use Connect family to manually connect to the wall. Connect Fire Rating still works as expected, so copy&paste would not be an issue.