hi,team:

    my dag is 1 minute schedule,one parts dag state is success,but tasks state is not yet started in a dag:

![image](https://user-images.githubusercontent.com/41068725/116344664-357d8780-a819-11eb-8010-c746ffdfdbcc.png)


   how can to fix it?
tests/core/test_sqlalchemy_config.py
self.old_engine = settings.engine
        self.old_session = settings.Session
        self.old_conn = settings.SQL_ALCHEMY_CONN
        settings.SQL_ALCHEMY_CONN = "mysql+foobar://user:pass@host/dbname?inline=param&another=param"
    def tearDown(self):
        settings.engine = self.old_engine
        settings.Session = self.old_session
        settings.SQL_ALCHEMY_CONN = self.old_conn
    @patch('airflow.settings.setup_event_handlers')
    @patch('airflow.settings.scoped_session')
    @patch('airflow.settings.sessionmaker')
    @patch('airflow.settings.create_engine')
    def test_configure_orm_with_default_values(
        self, mock_create_engine, mock_sessionmaker, mock_scoped_session, mock_setup_event_handlers
    ):
        settings.configure_orm()
        mock_create_engine.assert_called_once_with(
            settings.SQL_ALCHEMY_CONN,
            connect_args={},
            encoding='utf-8',
            max_overflow=10,
            pool_pre_ping=True,
            pool_recycle=1800,
            pool_size=5,
        )
    @patch('airflow.settings.setup_event_handlers')
    @patch('airflow.settings.scoped_session')
    @patch('airflow.settings.sessionmaker')
    @patch('airflow.settings.create_engine')
    def test_sql_alchemy_connect_args(