Per BF-26091, the use of transportLayerASIOhangBeforeAccept failpoint does not guarantee that the connection from mongos to the primary will wait longer than the configured threshold, because the failpoint can be hit by any incomming connection, not just the one from mongos. That makes the connection_establishment_metrics.js test fail occasionally, because the connection from mongos doesn't get stalled long enough.

Increasing the wait time after the failpoint has been activated should fix the problem.