GitHub user Komalpawar22 edited a discussion: Clearing tasks from old DAG runs 
resets start_date instead of preserving original

# DAG run `start_date` is overwritten when clearing old tasks

## Apache Airflow version
2.10.4

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## What happened
When clearing a task from an *old DAG run*, the DAG run’s `start_date` gets 
updated to the current timestamp.  
This makes the old run appear as if it just started “today,” even though it 
originally ran days or weeks ago.

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## What you expected to happen
- The DAG run’s `start_date` should remain fixed to its original value (when 
the run was first created).  
- Only the `end_date` or task-level timestamps should update when 
clearing/retrying tasks.  
- `start_date` should act as an immutable record of when the DAG run first 
started.

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## How to reproduce
1. Trigger a manual DAG run (e.g. `manual__2025-07-25T00:00:00+00:00`).  
2. Note the run’s `start_date`.  
3. Wait (days/weeks).  
4. Clear one of the tasks in that old run.  
5. Observe that the DAG run’s `start_date` is now updated to the current time.

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## Anything else
- This behavior feels confusing and counterintuitive.  
- From a user perspective, `start_date` looks like a historical field and 
shouldn’t change after the fact.  
- Is this behavior **intended**?  
- If not, are there any fixes or changes in newer versions of Airflow?  

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GitHub link: https://github.com/apache/airflow/discussions/55206

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