One new scene object, adds two?

I've created a new type of object with the following code:

//-----------------------------------------------------------------------------
// Puzzle Object
//-----------------------------------------------------------------------------

#ifndef _PUZZLEBASE_H_
#define _PUZZLEBASE_H_

#ifndef _SHAPEBASE_H_
#include "game/shapeBase.h"
#endif

//----------------------------------------------------------------------------

struct PuzzleBaseData: public ShapeBaseData
{
	typedef ShapeBaseData Parent;

	//
	PuzzleBaseData();
	DECLARE_CONOBJECT(PuzzleBaseData);

	//
	static void initPersistFields();
};

//----------------------------------------------------------------------------

class PuzzleBase: public ShapeBase
{
	typedef ShapeBase Parent;

  protected:
	PuzzleBaseData* mDataBlock;

  protected:
	//
	bool onAdd();
	void onRemove();
	bool onNewDataBlock(GameBaseData* dptr);

  public:
    //
	DECLARE_CONOBJECT(PuzzleBase);
	static void initPersistFields();

	//
	PuzzleBase();
	~PuzzleBase();
};

#endif


// Part of the CC file
bool PuzzleBase::onAdd()
{
	if(!Parent::onAdd())
		return false;

	addToScene();

	if (isServerObject())
		scriptOnAdd();

	Con::printf("PuzzleShape: %d", getId());

	return true;
}

When I create the object in the game, it will add it nicely, at least on the surface. The "onAdd" function is called twice generating two different ID's. One object holds the shape of the object and the other is the actual object (%object = new PuzzleShape(DatablockName); ).

Am I doing something wrong for my object creation?