**Apache Airflow version**: 2.0.0


**Kubernetes version (if you are using kubernetes)** (use `kubectl version`):

**Environment**:

- **Cloud provider or hardware configuration**:
- **OS** (e.g. from /etc/os-release):
- **Kernel** (e.g. `uname -a`):
- **Install tools**:
- **Others**:

**What happened**:

I have the following DAG:

```py
from datetime import datetime, timedelta

from airflow import DAG
from airflow.operators.bash_operator import BashOperator

with DAG(
    dag_id="sla_trigger",
    schedule_interval="* * * * *",
    start_date=datetime(2020, 2, 3),
) as dag:
    BashOperator(
        task_id="bash_task",
        bash_command="sleep 30",
        sla=timedelta(seconds=2),
    )

```

And in my understanding this dag should result in SLA miss every time it is triggered (every minute). However, after few minutes of running I don't see any SLA misses...

**What you expected to happen**:

I expect to see SLA if task takes longer than expected.

**How to reproduce it**:

Use the dag from above.

**Anything else we need to know**:

N/A

tests/jobs/test_scheduler_job.py
)
        dr2 = dag.create_dagrun(
            run_type=DagRunType.BACKFILL_JOB,
            state=State.RUNNING,
            execution_date=DEFAULT_DATE + datetime.timedelta(1),
            start_date=DEFAULT_DATE,
            session=session,
        )
        ti = dr.get_task_instance(task_id=op1.task_id, session=session)
        ti.state = State.SCHEDULED
        ti2 = dr2.get_task_instance(task_id=op1.task_id, session=session)
        ti2.state = State.SCHEDULED
        session.commit()
        processor = mock.MagicMock()
        scheduler = SchedulerJob(num_runs=0)
        scheduler.processor_agent = processor
        scheduler.adopt_or_reset_orphaned_tasks()
        ti = dr.get_task_instance(task_id=op1.task_id, session=session)
        assert ti.state == State.NONE
        ti2 = dr2.get_task_instance(task_id=op1.task_id, session=session)
        assert ti2.state == State.SCHEDULED, "Tasks run by Backfill Jobs should not be reset"
    @parameterized.expand(
        [
            [State.UP_FOR_RETRY, State.FAILED],
            [State.QUEUED, State.NONE],
            [State.SCHEDULED, State.NONE],
            [State.UP_FOR_RESCHEDULE, State.NONE],
        ]
    )
    def test_scheduler_loop_should_change_state_for_tis_without_dagrun(