How debugging Apache Airflow lead to Adyens Airflow contributions

Apache Airflow is an orchestration framework for batch jobs heavily relied on by Adyen. A couple days after we deployed the new Airflow 2.0 version on our live environments we were noticing tasks becoming stuck. After multiple long debugging sessions, we found the culprit. By introducing three simple lines we solved our problem and were able to contribute an important fix to the open source community.