During March 2026, Sam focused on improving the reliability of Apache Airflow’s High-Availability scheduler by addressing a subtle bug in downstream task skipping. He developed a state-aware guard within the scheduler logic that prevents tasks in RUNNING, SUCCESS, or FAILED states from being inadvertently overwritten to SKIPPED, particularly in clustered deployments. This update, implemented in Python and leveraging backend development and database management skills, reduced heartbeat conflicts and mid-execution failures by ensuring downstream skip decisions respect in-flight task states. Sam’s work in the apache/airflow repository enhanced the correctness of task state transitions, contributing to more robust HA scheduler behavior in production environments.