No more dagruns after changing schedule interval #66754

Under which category would you file this issue?

Airflow Core

Apache Airflow version

3.2.1

What happened and how to reproduce it?

After updating the Dag schedule from 0 * * * * to 0 0 * * *, no more dagruns were created. The scheduler started outputting these logs.

2026-05-12T05:04:45.798844Z [warning  ] run already exists; skipping dagrun creation [airflow.jobs.scheduler_job_runner.SchedulerJobRunner] dag_id=schedule_change loc=scheduler_job_runner.py:1958 logical_date=datetime.datetime(2026, 5, 4, 0, 0, tzinfo=Timezone('UTC'))

I was able to reproduce the behaviour with the following Dag.

from airflow.models import DAG
from airflow.decorators import task
from datetime import datetime

with DAG(
    dag_id="schedule_change",
    start_date=datetime(2026, 5, 4),
    end_date=datetime(2026, 5, 4,
    schedule='0 * * * *',
    catchup=True,
    max_active_runs=1,
) as dag:

    @task
    def do_something():
        import time
        time.sleep(1)

    do_something()

Once unapused, one dagruns with run_id scheduled__2026-05-04T01:00:00+00:00 and logical date 2026-05-04 00:00:00 is created. Next, remove the end_date parameter and update the schedule interval to "0 * * * *" (run daily) from "0 0 * * *" (run hourly). The expected behaviour is for a new dagrun with logical date 2026-05-05 00:00:00 to be created. However, no dagrun is created at all.

The scheduler did attempt to create a dagrun but a dagrun with the expected logical date already exist.

One important thing to note is that the deployment uses CronDataIntervalTimetable since AIRFLOW__SCHEDULER__CREATE_CRON_DATA_INTERVALS==True.

What you think should happen instead?

I think the scheduler should create a dagrun with logical date 2026-05-05 00:00:00 but instead it is stuck trying to create a dagrun with logical date 2026-05-04 00:00:00.

Operating System

No response

Deployment

Astronomer

Apache Airflow Provider(s)

No response

Versions of Apache Airflow Providers

No response

Official Helm Chart version

Not Applicable

Kubernetes Version

No response

Helm Chart configuration

No response

Docker Image customizations

No response

Anything else?

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct