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?
airflow/settings.py
import json
import logging
import os
import sys
import warnings
from typing import Optional
import pendulum
from sqlalchemy import create_engine, exc
from sqlalchemy.engine import Engine
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.orm.session import Session as SASession
from sqlalchemy.pool import NullPool
from airflow.configuration import AIRFLOW_HOME, WEBSERVER_CONFIG, conf  
from airflow.executors import executor_constants
from airflow.logging_config import configure_logging
from airflow.utils.orm_event_handlers import setup_event_handlers
log = logging.getLogger(__name__)
TIMEZONE = pendulum.tz.timezone('UTC')
try:
    tz = conf.get("core", "default_timezone")
    if tz == "system":
        TIMEZONE = pendulum.tz.local_timezone()
    else:
        TIMEZONE = pendulum.tz.timezone(tz)
except Exception:  
    pass
log.info("Configured default timezone %s", TIMEZONE)
HEADER = '\n'.join(
    [
        r'  ____________       _____________',