Task State Changed Externally by Scheduler
warningTasks fail or change state not by executor action but by scheduler intervention (e.g., parsing timeout, queue timeout, heartbeat timeout), causing confusion when reviewing logs and indicating resource or configuration issues.
Detect when task state changes occur outside normal executor flow: check for scheduler-marked failures due to dagbag_import_timeout, dag_file_processor_timeout, task_queued_timeout, or heartbeat timeout events in scheduler logs and task instance state transitions.
Increase core.dagbag_import_timeout and dag_processor.dag_file_processor_timeout if parsing is slow; increase scheduler.task_queued_timeout if tasks queue too long; investigate worker resource exhaustion or network issues if heartbeat timeouts occur; review scheduler and worker logs for root cause.