fragmentManager.findFragmentByTag sometime cannot find an attaching BindingFragment

[microstudent]

when binding on Activity/Fragment onCreate() , Rxlifecycle would add an bindingFragment, look like this:

protected void onCreate(Bundle savedInstanceState) {
    	Log.d(TAG, "" + "ActionBarActivity onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_jnitest);
 
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment(), "myfragment")
                    .commit();
        }
        Log.d(TAG, "Fragment:"+getSupportFragmentManager().findFragmentById(R.id.container));

findFragmentById will return null.
if we bind lifeCycle during onCreate() more than once, which is very common to do such as load a lot of data, it would attach more than one BindingFragment !
and it seems to be wrong.