Handrail exists without its geometry.
Handrail must have a relation with its input (geometry).
Handrail becomes orphaned.
What You Should Do
Ask your database administrator to back up the model.
Supply all information possible that might have led to this situation, and submit this information along with the backup to Hexagon PPM Support.
Open the model.
Locate and select the offending handrail, and delete it.