Why aren't they convergent?

[dancheng9999]

package student

type Person struct { name string }

type Student struct { person Person }

run command goplantuml -recursive -output ./uml/main.puml ./

@startuml namespace student { class Person << (S,Aquamarine) >> { - name string

}
class Student << (S,Aquamarine) >> {
    - person Person

}

}

@enduml