Orphaned structure member part end port.
Every member part has two end ports related to it (the end port at the start of the member and the end port at the end of the member). When the member part was deleted, one of the end ports was not deleted along with the member part.
Deleting a member part failed to propagate the delete operation to one or more of its end ports.
What You Should Do
Run the delivered custom command to remove the offending port.
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.
Execute the Clean Database custom command to remove the port.