Tested with both chart 1.1.0rc1 (i.e. main branch r.n.) and 1.0.0 

in Airflow 2.1.0, scheduler does not exit immediately (this was an issue < 2.1.0), but all tasks fail like this:

```
2021-06-08 15:30:17,167] {scheduler_job.py:1241} ERROR - Executor reports task instance <TaskInstance: sqoop_acquisition.terminate_job_flow 2021-06-08 13:00:00+00:00 [queued]> finished (failed) although the task says its queued. (Info: None) Was the task killed externally?
[2021-06-08 15:30:17,170] {scheduler_job.py:1241} ERROR - Executor reports task instance <TaskInstance: gsheets.state_mapping.to_s3 2021-06-08 14:00:00+00:00 [queued]> finished (failed) although the task says its queued. (Info: None) Was the task killed externally?
[2021-06-08 15:30:17,171] {scheduler_job.py:1241} ERROR - Executor reports task instance <TaskInstance: gsheets.app_event_taxonomy.to_s3 2021-06-08 14:00:00+00:00 [queued]> finished (failed) although the task says its queued. (Info: None) Was the task killed externally?
[2021-06-08 15:30:17,172] {scheduler_job.py:1241} ERROR - Executor reports task instance <TaskInstance: gsheets.strain_flavors.to_s3 2021-06-08 14:00:00+00:00 [queued]> finished (failed) although the task says its queued. (Info: None) Was the task killed externally?
[2021-06-08 15:30:19,053] {scheduler_job.py:1205} INFO - Executor reports execution of reporting_8hr.dev.cannalytics.feature_duration.sql execution_date=2021-06-08 07:00:00+00:00 exited with status failed for try_number 1
[2021-06-08 15:30:19,125] {scheduler_job.py:1241} ERROR - Executor reports task instance <TaskInstance: reporting_8hr.dev.cannalytics.feature_duration.sql 2021-06-08 07:00:00+00:00 [queued]> finished (failed) although the task says its queued. (Info: None) Was the task killed externally?
[2021-06-08 15:30:23,842] {dagrun.py:429} ERROR - Marking run <DagRun gsheets @ 2021-06-08 14:00:00+00:00: scheduled__2021-06-08T14:00:00+00:00, externally triggered: False> failed
```

@kaxil @jedcunningham  do you see this when you run CKE?  Any suggestions?
airflow/jobs/base_job.py
)
    state = Column(String(20))
    job_type = Column(String(30))
    start_date = Column(UtcDateTime())
    end_date = Column(UtcDateTime())
    latest_heartbeat = Column(UtcDateTime())
    executor_class = Column(String(500))
    hostname = Column(String(500))
    unixname = Column(String(1000))
    __mapper_args__ = {'polymorphic_on': job_type, 'polymorphic_identity': 'BaseJob'}
    __table_args__ = (
        Index('job_type_heart', job_type, latest_heartbeat),
        Index('idx_job_state_heartbeat', state, latest_heartbeat),
    )
    task_instances_enqueued = relationship(
        TaskInstance,
        primaryjoin=id == foreign(TaskInstance.queued_by_job_id),
        backref=backref('queued_by_job', uselist=False),
    )
    dag_runs = relationship(
        DagRun,
        primaryjoin=id == foreign(DagRun.creating_job_id),
        backref=backref('creating_job'),
    )
    """
    TaskInstances which have been enqueued by this Job.
    Only makes sense for SchedulerJob and BackfillJob instances.
    """
    heartrate = conf.getfloat('scheduler', 'JOB_HEARTBEAT_SEC')
    def __init__(self, executor=None, heartrate=None, *args, **kwargs):