StandAlone StructPortSelector not associated to a StructGenericEntity.
The StructPortSelector is not a first class business object, but it is used in the geometries graph of a business object in order to expose its ports.
This object actually makes the link between a port and its source geometry. So the problem is similar to the one represented by the Orphaned Struct Port error.
Dependent objects may not be able to update their geometry correctly.
What You Should Do
Open the model.
Delete the object.