title: Apache-Airflow - Task is in the none state when running DAG
body: <p><em>Just started with airflow and wanted to run simple dag with BashOperator that outputs 'Hello' to console</em>
  I noticed that my status is indefinitely stuck in 'Running'</p>
  <p>When I go on task details, I get this:</p>
  <p><strong>Task is in the 'None' state which is not a valid state for execution. The task must be cleared in order to be run.</strong></p>
  <p>Any suggestions or hints are much appreciated.</p>
  <p>Dag:</p>
  <pre><code>from datetime import timedelta
  from airflow import DAG
  from airflow.operators.bash_operator import BashOperator
  from airflow.utils.dates import days_ago
  
  default_args = {
      'owner': 'dude_whose_doors_open_like_this_-W-',
      'depends_on_past': False,
      'start_date': days_ago(2),
      'email': ['yessure@gmail.com'],
      'email_on_failure': True,
      'email_on_retry': True,
      'retries': 1,
      'retry_delay': timedelta(minutes=5),
  }
  dag = DAG(
      'Test',
      default_args=default_args,
      description='Test',
      schedule_interval=timedelta(days=1)
  )
  
  t1 = BashOperator(
      task_id='ECHO',
      bash_command='echo &quot;Hello&quot;',
      dag=dag
  )
  
  t1
  </code></pre>