fritz-astronomer opened a new issue, #54201:
URL: https://github.com/apache/airflow/issues/54201
### Apache Airflow version
3.0.3
### If "Other Airflow 2 version" selected, which one?
_No response_
### What happened?
I had a DAG, which briefly had the following:
```
with DAG(
dag_id="sync",
max_active_tasks=1,
...
):
```
`max_active_tasks` was later removed, now it's:
```
with DAG(
dag_id="sync",
...
):
```
However, the `max_active_tasks` seems to have persisted? This seems to be
happening across restarts and Dag reparses, as well.
```
2025-08-06T17:10:21.270406000-04:00[2025-08-06T21:10:21.269+0000]
{scheduler_job_runner.py:523} INFO - DAG sync has 1/1 running and queued tasks
2025-08-06T17:10:21.270408000-04:00[2025-08-06T21:10:21.269+0000]
{scheduler_job_runner.py:530} INFO - Not executing <TaskInstance: sync.foo
manual__2025-08-06T21:03:41.243617+00:00 [scheduled]> since the number of tasks
running or queued from DAG sync is >= to the DAG's max_active_tasks limit of 1
```
I've checked and I'm not setting that anywhere else across the project, nor
in environment variables nor anything else.
Checking the database, locally, I see that `max_active_tasks=1`
```pycon
$ astro dev bash
# python
>>> from airflow.settings import Session; import json; from pprint import
pprint; import pandas
>>> pprint(json.dumps(pandas.read_sql("select * from dag where
dag_id='sync';", Session().connection()).to_dict(orient="records"), indent=2,
default=str))
('[\n'
' {\n'
' "dag_id": "sync",\n'
' "is_paused": false,\n'
' "is_stale": true,\n'
' "last_parsed_time": "2025-08-06 21:40:28.220637+00:00",\n'
' "last_expired": null,\n'
' "fileloc": "/usr/local/airflow/dags/sync.py",\n'
' "relative_fileloc": "sync.py",\n'
' "bundle_name": "dags-folder",\n'
' "bundle_version": null,\n'
' "owners": "airflow",\n'
' "dag_display_name": null,\n'
' "description": null,\n'
' "timetable_summary": "None",\n'
' "timetable_description": "Never, external triggers only",\n'
' "asset_expression": null,\n'
' "max_active_tasks": 1,\n'
' "max_active_runs": 16,\n'
' "max_consecutive_failed_dag_runs": 0,\n'
' "has_task_concurrency_limits": false,\n'
' "has_import_errors": true,\n'
' "next_dagrun": null,\n'
' "next_dagrun_data_interval_start": null,\n'
' "next_dagrun_data_interval_end": null,\n'
' "next_dagrun_create_after": null\n'
' }\n'
']')
```
the default looks like it's 16?
https://github.com/apache/airflow/blob/main/task-sdk/src/airflow/sdk/definitions/dag.py#L402
(though, I couldn't find this in documentation anywhere, unfortunately - but
that's a separate issue)
### What you think should happen instead?
_No response_
### How to reproduce
^
### Operating System
Astro / Debian
### Versions of Apache Airflow Providers
_No response_
### Deployment
Astronomer
### Deployment details
_No response_
### Anything else?
_No response_
### Are you willing to submit PR?
- [ ] Yes I am willing to submit a PR!
### Code of Conduct
- [x] I agree to follow this project's [Code of
Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)
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