The suite steps down the config server primary every 8 seconds. The test calls waitForClusterTime, which runs _configsvrGetHistoricalPlacement against the config primary (jstests/libs/query/change_stream_util.js:1509). If the call lands during a stepdown, the command returns an error with no historicalPlacement field. The helper then throws can't access property "status", ... historicalPlacement is undefined.