delphi – 调用TObjectList.Clear时,不会释放TObjectList中的对

IObserver = interface
    ['{1DD212F8-BD5E-47BF-9A3B-39EF7B9D99B5}']
    procedure Update(Observable: IObservable);
  end;

  TObserver = class abstract (TSingletonImplementation,IObserver)
    strict protected
      //...
    public
      constructor Create;
      destructor Destroy; virtual;
      //IObserver
      procedure Update(Observable: IObservable); virtual; abstract;
      //... 
  end;

  TShapeModification = class abstract (TObserver)
    strict protected
      //...
    public
      //Doesn't have a constructor
  end;

  TRangePointModification = class(TShapeModification)
    strict private
      //...
    public
      constructor Create(...);
      //...
  end;

  constructor TRangePointModification.Create(...);
  begin
    inherited Create;
    //...
  end;

然后在某个时候：

TClientClass = class
  strict private
    fList: TObjectList<TShapeModification>;
  public
    constructor Create();
    destructor Destroy(); override;
    procedure Add(ShapeModification: TShapeModification);
end;

constructor TClientClass.Create;
begin
  Self.fList:=TObjectList<TShapeModification>.Create(true);
end;

destructor TClientClass.Destroy;
begin
  Self.fList.Clear;
  FreeAndNil(Self.fList);
end;

最后,在某些时候：

var
  MyClient: TClientClass;
begin
  MyClient:=TClientClass.Create();
  MyClient.Add(TRangePointModification.Create());
  MyClient.Free;
end;

当释放MyClient时,调用TClientClass析构函数然后应该清除内部fList,但不调用TRangePointModification(来自TObserver)的析构函数.为什么不？

(我使用的是Delphi 10.2 Tokyo)