Issue with on_failure_callback on task level

[pskrobich]

Hello,

I'm experiencing an issue in airflow 3.0.6 where the on_failure_callback is not executing when configured at the task level via default_args, while the on_success_callback works correctly.

Current DAG Configuration:

@dag(
    schedule='*/20 * * * *',
    default_args={
        'on_failure_callback': slack_notification_callback,
        'on_success_callback': slack_notification_callback
    },
)

Problem:

• Success callbacks trigger correctly after each task completion and send Slack notifications
• Failure callbacks do not trigger at all when tasks fail
• Both callbacks use the same function (slack_notification_callback) for Slack notifications

I specifically need task-level callbacks rather than DAG-level callbacks because with DAG-level callbacks, I cannot identify which specific task failed, making it difficult to provide meaningful failure notifications.

@dag(
    schedule='*/20 * * * *',
    on_failure_callback= slack_notification_callback,
    on_success_callback= slack_notification_callback
)

Is this a known issue with task-level failure callbacks in default_args? Are there any workarounds to ensure failure callbacks execute at the task level while maintaining access to task-specific information?