After exporting 3D views that have been cut with a scope/section box from Revit 2024 using the "Publish to NWC" add-in, the NWC file opens in Navisworks with sectioning enabled by default.
Disabling sectioning for such views will reveal full extents of elements within the visible (cropped-in) part of the model. Only the completely cropped out elements are truly cut out.
If rooms were exported from Revit, disabling sectioning will also reveal all cut-out rooms in translucent mode.
This behavior was not observed when exporting to NWC in previous versions (Revit 2023 and older).
This is the new default behavior and is a change to previous versions, and is working in Revit 2024 as designed.
In Revit 2024, the add-in has been updated to reveal the full geometry of elements which are within the visible portion of the cropped view when the sectioning tool is disabled. This portion is 'hidden' via the sectioning tool by default when opened in Navisworks.
You can provide feedback about this change on the Revit Idea station.